Most of the time I feel meanness is a maturity thing. Often a way of building oneself up by putting others down.
Many years ago I built a gaming computer for/with my kids. I used pcpartpicker.com to find and keep track of the build. I also posted a write-up on the build and the trade-offs I made. There was a lot of polite feedback but one person in particular stood out ... basically stating that I was that I was an "idiot" for using several parts in my build (I don't think he read the write-up). One example was my PSU. Only an idiot would buy from from an unknown company (in this case Seasonic) and that I should have bought from a company like Corsair. I thought that very funny and pointed out the Seasonic made many of Corsair's higher end PSUs. I had similar comments on each of his issues.
In any case I also I think we've all made posts we regret ... for me it's when I answer too quickly, say something in absolutes, something which can be misinterpreted, or of poor tone. I alway reread my posts but a lot of times don't catch the tone or how it could come off because I still have my intent in my head. It's when I re-read it a day later that I realize that the words do not match that intent and then I'm embarrassed. I never want to say "your wrong", "I know better", or "your an idiot" (although I may think it). It's why I try and qualify stuff with, I think, I believe, or in my opinion as often as I can.
