But I also find the psychology behind this sort of reply interesting, because there's lots of factors that lead to this sort of extreme.

Firstly, we don't know the age of the replier, but my guess would be someone also young, or at least immature. Telling people to kill themselves is not something adults typically do in any context.)

So it suggests another junior, desperate to prove their own standing, and needing to compete against others rather than collaborate. I've seen this kind of response in one adult (abusive to other forum members) but he clearly had quite severe mental health issues (and the user was banned.) In youngsters it is usually extinguished with firm moderator guidance.

With adult responders, frustration and tedium play a role. Personally I'm more generous with replies in the morning than the evening. At times I almost "fake" patience (when I'm getting impatient) with people who are simply not thinking, and who aren't listening.

Overall it is very imbalanced. The asker is asking 1 question. The replier may answer tens or hundreds in a day. So it's hard to answer each one as if it's original, as if it matters, as if you've not heard it a million times before (especially if it's right there in the FAQ.)

Part of answering well, and the quality of any forum, is in participants answering well, even if the question is trivial.

We all were newbies once. Asking stupid questions is how we grew from there. Answering stupid questions is how we pay it forward.