This is interesting - but I think you are misunderstanding the nature of both 'western liberal democracy' (especially regarding institutions and culture) and of 'authoritarianism'.
It's not just 'political structure'.
In fact, I think your points help to illustrate the general misunderstanding happening here.
>>> "Korea votes, and the protest against injustice"
Really? No abortion? No gay marriage?
Where are the protests?
Now - I'm not taking a position pro/against those issues - what I'm saying is that those are subject to interpretation.
'Protesting injustice' is not 'liberal democracy'.
In fact, popular protests against perceived injustice could actually be a sign of authoritarian populism i.e. 'Law and Order' regimes.
Koreans are strongly ethnocentric (in-group vs. out-group), they have a very strong, nationalist sentimentality. They have compulsory military service and no problem filling the ranks. They are very traditional, they absolutely support Korean culture as 'normative', they support traditional marriage, traditional family hierarchy. I think it's fair to say that Korea is essential 'patriarchial' both in culture and business but also politics.
Korea values strongly 'national industrial champions' like Samsung ('Chaebols') [1] etc.. The economy is considerably more centralized under the power of this small elite of ruling families than elsewhere. Employees are often actually loyal to these 'families' as they work their entire lives, and 'play their part' in building a 'greater Korea'.
Here is one description of 'Chaebol': "A chaebol often consists of many diversified affiliates, controlled by an owner whose power over the group often exceeds legal authority." (from [1]). This is a pretty powerful statement of authoritarianism.
Of course, from 1955 until only about 20 years ago, Korea was point-blank a 'centrally planned economy' and such systems don't change overnight.
Social behaviours are codified, and deviation will come with 'social shaming'. Actually - this very term 'social shaming' really helps differentiate between US and Korea: 'social shaming' would be seen as mostly a negative artifact in a liberal society, whereas I believe most Koreans would support the kinds of subtle shaming that can be pervasive (my evidence being the fact that such shaming is commonplace). This is an example of systematic authoritarianism, and a specific artifact called right out in the paper as 'social conformity'.
'Getting mad at a strong man' is not an example of 'anti-authoritarianism' - because usually, the strong man is replaced by another one they like ... until they get mad at him as well.
Even though 'they vote a lot' as you say, for the most part, most would argue that Korea is not a 'Western Liberal Democracy' in the broader sense of the term.
And yes, by the way, I agree they're probably not interested in 'individual strong men' quite as much as Russians for example, but systematically, it's still authoritarian.
Korea, Japan, Singapore - similar.
>>>>> The US actually has a problem because our government is a bit too centralized.
I'm sorry but this is just not true, the US is a highly decentralized nation.
In Korea (as in France, Sweden for example) - political, industrial, military, and even cultural centres like the elite Universities, Media, Publications - all have a much tighter relationship with one another and are centralized.
The US doesn't even have a state broadcaster, they have no direct means to communicate with the people.
US Pres. has very limited powers to direct certain activities in normal times. Yes - he can declare 'emergency' powers to do 'some things' - but even then, he does not have the apparatus in place as an instrument of control. He can make 'orders' but where are the agencies to effectuate such orders? He has the military, the IRS. There is no national healthcare system. The pandemic response is hugely fragmented.
Look at how America is responding to the crises: Fed programs, indirect payout programs - these are all 'bigger versions' of things they would do in normal times.
Whereas Trump materially and specifically interjected? He stopped some air travel - but has he coordinated policy? Purchasing? Testing? Not really. He has 'invited' market participants!
You can see America trying to react to this situation on America's strengths (indirect intervention, capitalism, market solutions, distributed authority), which is failing them.
>>>>>>>>>> Strong leadership is different from authoritarianism.
Yes - your point is taken - if we were talking about a CEO, then it would be especially relevant. But in this context, it's not so important.
'Bill Clinton' is an inspiring, the great moral leader in many ways, you could say 'strong leader' but he's the last person we want in charge right now.
A true 'strong leader' with 'authoritarian tendencies' but who very thankfully understood the risk of it - would be Dwight D. Eisenhower.
Eisenhower was not so very 'inspiring' (not like Obama), and he was not a great communicator. But he was absolutely a competent, effective operator, and ruthless if he needed to be. He was Supreme Nato Allied Commander: simple, austere, efficient, down-to-earth but politically nimble, brilliant, 'non-populist', humble, dispassionate manager of mass violence.
But he's totally unlike Trump - who I think is the 'bad kind of strong man' (i.e. aggressive, crude, arrogant, but actually incompetent). The key to understanding his popularity is that many people actually do believe him when he says 'I'm a genius'.
So if Trump was, like Eisenhower: patriotic, loyal, dedicated, organized, competent, then 'authoritarianism' would be good in times like this.
Example: the states are all in a bidding war over PPE, ventilators, there's a lack of coordination, too much will be paid, deliveries won't be optimized etc.
A benevolent central power like Eisenhower would have acted long ago, set temporary price controls on items, set production levels, required isolation by law and had the apparatus to effectuate it (i.e. 'workers' to go to homes, check on health, make sure nobody is cheating). Testing would have been mandatory and prevalent, and he would have demanded that you give up your movement history, which citizens would have accepted due to the nature of the situation.
During WW2 and shortly afterwards - Eisenhower was a 'strong leader' a 'great example', but he was also definitely an authoritarian and a little bit of a strong man as well, by definition, as a military general.
FYI that's why Eisenhower type leaders aren't elected long after wars!
Summary:
+ Korea is institutionally and culturally much more authoritarian than the West.
+ Authoritarianism is generally misunderstood, miscommunicated
+ People living in 'Western Liberal Democracies' sometimes have difficulty with this one, having little exposure to anything else.
+ All of the modern nations that 'tend centrally planned' have actually responded well to coronavirus, all of the 'liberal democracies' are in general disarray - and this is precisely due to the operational competence of some of the 'more authoritarian systems'.
+ This is not evidence of superiority, nor is it evidence that certain kinds of authoritarianism won't fail: Russia, I believe, if it is 'hit hard' by coronavirus, will be devastated, as will obviously very poor, totally corrupt nations around the world with zero operational competence but who have 'strong man' leaders.
[1] https://en.wikipedia.org/wiki/Chaebol