> how did my country turn into this?
There are two components to this answer.
First, your country has been divided since at least the mid-19th century. Every war has a winning and losing side, but the losers don't simply vanish. Their mentality persists throughout generations, even if it remains in the background, and is ignored by the other side.
Secondly, all this technology you've built and allowed the world to use can and has been exploited by your enemies to your own detriment. The same systems you've built that allow manipulating people into buying things are also ideal channels for spreading propaganda and disinformation. Information warfare is not new, but modern technology has made it more effective than ever at manipulating groups of people, sowing dissent, and generally causing chaos and confusion within a nation.
So, putting those two together, it's not difficult to see how acts of information warfare could be used to fuel the deeply rooted social divide, directly causing or strongly contributing to the internal sociopolitical instability you've been experiencing for the past decade.
Meanwhile, your enemies can sit back and enjoy the show of an imploding nation. They know that you're untouchable via traditional warfare, which is why these tactics are so perfect. They do require a long time to come into effect, but they're highly effective, very cheap to deploy, and the best part is that they're completely untraceable to the attacker. It's still debatable whether there was Russian interference in your elections, and how effective it actually was, even though there is evidence for it. It's still debatable whether Chinese-operated social media platforms are a national security threat or not. Were J6 protesters rioters or patriots? And so on about every controversial sociopolitical topic.
This confusion is exactly the intended effect. Your regular checks and balances, your laws, ideals and values, make no difference if your communication channels are corrupted.
I don't see how you can get out of this mess, and I expect things will get much worse before they get better. Not just for you, but globally. These same tactics are also deployed in other countries, by the US as well. Though, ironically, countries that are cut off from the global internet have an upper hand in this conflict.