In general I've found that the "suck it up" and "thicker skin" types are the ones with the thinnest skin. A little empathy and compassion never hurt anyone, and part of growing is realizing that what you say and do to other people has a real effect. Nobody's perfect, and we'll all have days where we're snippy with someone because of what's going on with us, but what's important is trying your best to control it and defuse a situation if one arises.

As far as forums themselves, the only way to discourage the kind of hostile and low effort arguments we're thinking about is heavy moderation. Communities won't police themselves, and toxic people corrupt those around them by driving away reasonable people who are discouraged by the vitriol, and encouraging those that remain to play at the same level. Of course, heavy moderation brings its own set of problems. I always hear people say you'll get banned easily on these forums, but I've taken some hard stances over the past few years on controversial topics and I haven't seen a ban once. I think what's most important is, if you're going to make a strong statement, to make it in good faith and with a clear contribution to the discussion as opposed to flame bait or drive-by posting.