My theory is that some folks here really value the perceived freedom to not spare people's feelings with their posts/comments. I assume these folks experience the implied obligation in other social contexts to spare people's feelings as onerous, though of course I don't know.

Of course, that doesn't mean they actually go around hurting people's feelings all the time, no matter how much they may value the fact that they are free to do so.

Meanwhile, other folks carry on being kind/attentive/polite. I assume they don't consider this an onerous obligation and behave here more or less as they do elsewhere along this axis.

And the sorts of folks who in most Internet channels create most of the emotional disturbance don't seem to post much at all... either because karma works, or because they haven't found the place, or because the admins are really good at filtering them out, or because the conversations here bore them, or some combination of those and other reasons.

The end result seems to be a "nice" level noticeably higher than most of the Internet, coupled with strong emotional support for not being "nice." I found the dichotomy a little bewildering at first, but I'm kind of used to it now.