[shebasan]

I have had several instances now where I am playing a small game like Express or Goulash, and another player sends me a private message to the effect that I should not be playing bridge, I am a terrible player, it is rude for me to play. Very demeaning comments and contrary to what the sites always say: be polite, etc. I don't know how to report this or whether to even bother, but I would like to know what others think.

[mycroft]

I'm very sorry this happens to you. I say that there is only one bad way to play bridge, and that's to stop playing - or stop someone else from playing. I wish it didn't happen; but I know it does.

Mark as enemy. Last private message they will send you. (I also mark in the player notes why I enemied them - which is interesting 5 or 6 years later, sometimes.)
Report to abuse@. Do not expect a response, specifically do not expect a response saying "we're doing this". But trust that they do, in fact, do things.
Find players you do like to play with and play with them. Individual tournaments are better than the Permanent Floating Pickup Pool in many ways, but can be worse as well (but at least you know that they'll go away after two or three boards). If the odd person making horrible comments affects you significantly, find partners and stop playing in games where you get "randoms" as partners.

You will not be able to do something on your own. You may not see what happens, and it may look like you're screaming into the void. But without marking, and reporting, they don't know - and others will be also screaming into the void.