Do I think anonymity helps people let loose with their lips and say things which they may not in a public place? Absolutely. I think anonymity on internet is a grossly misused comfort.
So, has this happened here? Certainly. It seems more so off late - but I think there is generally a cycle to all this.
Have the moderators admonished people every time? No - but this is not as easy as it sounds. There is a line of tolerance for each of us. But all of us expect moderators to come down when our subjective line of tolerance is crossed by a post. In other words, each one of us want moderators to behave "like us", but each one of us have differing views - hence our expectations can never be fulfilled. Some posts may cross the line of tolerances of most of us, and those are easy to moderate. Some others - get more tricky. Hence this will be an imperfect world.
If some of the active posters do not come down on posts that your perceive as harsh and slimy, does that mean they have given their tacit approval? No.
Are they taking sides if they comment on one, but not other? No - please dont be quick to judge.
But if they or someone defends a harsh post, you can disagree with them and certainly voice disapproval - but not because they chose not to post (you didnt say anything when XYZ said something, but now you are....).
For example, I used to be more active in this regard on sangeetham - asking people to tone down (particularly first time posters who register and post to bring down someone, or voice personal grievances). But that was like 10 years ago - I simply don't have the energy now to intervene most of the time (honest truth). Yes, many posts prick , but I sigh, and ignore it. I never liked harsh criticisms on artists on public forums - but doesn't mean i expressed by disapproval every time. If I had a $ for every time ....

!!.
Censorship from moderators may not be good. But self-censorship is very good. Freedom of Expression comes with responsibility. Let us not forget that.
Arun