*sigh*
OK, let's take this step by step.
1) He stated his opinion
2) You stated that his opinion demonstrated ignorance of the human condition (among other things, but let's focus). Now, the clear implication there is that knowledge of the human condition would somehow change his stance to match yours, or at the minimum move him in your direction. While I don't know that you actually stated it, it's not much of a reach should we infer that you feel your position is logically superior.
3) Since your opinion is being presented as "more correct" than his, then knowledge of the human condition must have some objective value, otherwise using it as a basis for the ranking of opinions is little more than intellectual wankery at best and intentional misdirection at worst.
4) I certainly wouldn't expect misdirection from you, and pointless pedantry defines a different poster far more than you. What's that leave?
When people are ignorant about a subject that I know a lot about - I find it's potentially useful and valuable to point it out and explain why. Not always, but certainly in cases like this.
That's the only reason I do it - because I'm trying to be utilitarian. I'm not sure if you can grasp the concept of no ego - but there is basically none involved. Except, of course, the part of me that believes I'm qualified to have an opinion about what's useful and that I should be allowed to speak about it openly.
That's also the reason I don't sugar-coat or try to manipulate the message. I try to "un-manipulate" all my messages in these cases, meaning I have no interest in diplomacy but exclusively in delivery. I find that people interpret that approach as if I'm trying to say something other than exactly what I'm saying, which is really awkward and annoying. So, I'm stuck between manipulating my message so as to avoid appearing like I'm being manipulative - or simply speaking as plainly as I can and living with appearing like there's a ton of underlying shit.
I chose the latter approach many years ago, and I can live with the consequences.
As for why I think it's useful? Well, the reason is that I consider ignorance about the human condition one of the primary factors in the misery of the world, as I stated above.
However, I can't prove or establish knowledge of the human condition as objectively valuable. That's pretty much impossible.
Essentially, it's not ignorance that's the problem - but our actions and inactions. I believe a lot of the harm being done to the world is based on ignorance - but if people would simply stop acting without sufficient knowledge in a lot of cases - we'd have a lot less misery.
Essentially, it's a very complex issue.
Also, I can't establish that "misery in the world" is objectively bad.
I suppose you might say that I hope to contribute to less misery in some way, and that less misery is better - based on what I personally think. But I like to leave it up to people to decide for themselves.
So, I stick to what I consider "correct" and "incorrect" as far as I'm able. Again, that's the only reason I stated what I did. Being incorrect, in this case, is believing that people living in a society that has "freedoms" can't have good (or understandable) reasons for killing themselves.
Conclusively, I'm not calling my superior knowledge about the human condition "better" - but simply superior. That's not objectively good - at least I can't prove that it is.