~Calm down. It's a common misconception.~
No, they shouldn't.
Moreover, being thought about how you're wrong about X might not necessarily translate in the subject being more careful before confidently expressing themselves on a Y topic on which they don't know anything about. Hopefully, ridiculing might make the subject reconsider that part of their character.
That said, the HN policies recommend to "be kind"... I have no idea how to "ridicule someone's post in a kind way" ¯\_(ツ)_/¯
If you can't educate the poster, at least you educate other readers who also didn’t know, without the unnecessary noise of ridicule.
I see that “Calm down. It's a common misconception” did get downvoted.
(And I think your comment is better without the ridicule! The sources you found for your follow-up comment are interesting and I learned from it.)
I agree ridicule should be used cautiously, but in a case like this where someone speaks so confidently and boldly gives advice on a topic they clearly do not understand, I think ridicule is a good way not only to inform them, but also indicate to others that it's not okay to give people this kind of advice unless you have a basic understanding of the topic.
I grew up in rural appalachia and the amount of grief than the uneducated get there for being uneducated causes them to become even more hostile and I really think that the Mr Rogers approach of education would eventually neuter any hostility they had towards the educated.
* edit: changed education to educated
As someone who does his taxes manually every year, this probably wouldn't help. Most people would be under the threshold and just look up the value in a table and not see how it scales.
If you use any sort of tax software I expect it's even further obscured.
0: https://carsey.unh.edu/publication/conspiracy-vs-science-sur...
1: https://www.aei.org/economics/survey-confirms-that-many-amer...
I dare say that it was probably the most common understanding until fairly recently. The internet has probably helped a lot with that. That is to say, if you're of a certain generation you probably think this way because that's what was generally understood.
I've used an accountant occasionally, but only when I had genuinely confusing tax issues involving international work or work across many states where I wasn't sure whether there existed a "nexus" that required me to pay taxes in State A or State B. Even then I did my best to double-check their work, and often caught errors/omissions. Most of my friends also do their own taxes (and have since 2006), regardless if they were line cooks or painters or engineers or MBB consultants. So I'm just not familiar with the lifestyles that lead to this.
I'd actually understand it more for people who've entered the workforce since 2005, because TurboTax/etc became much more popular. I did taxes with my dad in the mid-90's before most homes had internet, and back then it seemed far more likely that people would understand how taxes worked, because there wasn't super-easy software to do it for you.
Now I’m even more confused. Accountants were genuinely expensive and none of my peers in my economic class could afford one.
At the risk of repeating myself: how did you file taxes for the first decade of adulthood? If you were too poor pay an accountant like I was…how did you misunderstand how to calculate taxes owed for ten years, but still arrive at the correct amount to pay? Did the IRS often return money to you saying that you over-paid? Did anyone ever try to correct your misconception?
I’m trying to understand this in more detail than just “memorize the fact that 50% of Americans were lied to by (someone?) about taxes, and also just blindly accept that there is some magic unknown to me which allowed them to not be affected by that misunderstanding through most of their adult life”.
You were in poverty when you had this misunderstanding. This other commenter bought a house while they had the same misunderstanding. (So, “being poor” isn’t the experience you both had in common while holding this misconception and can’t explain it for both of you). I’m trying to understand how that misunderstanding never affected either of you. I’m trying to understand how neither of you ever had to read about how to calculate taxes owed.