At least in the CR, I’ve never seen one poster call another poster an “apikorus”. I have seen (especially in the much older threads) being mevazeh talmidei chachomim (most times as a group rather than individual.) Loshan hora has gotten through a lot on the main pages more than the CR. Taking credit for someone else’s words is a special problem in halacha (I think it removes bracha but is not an aveira), rather than sheker per se. Although many times when quoting another anonymous poster on another site, it is difficult to credit something anonymously, and this sites policy doesn’t allow links or competitors attributions. Considering the anonymity here, its hard to imagine posting someone elses secret, unless that persons first posted it (and presumably then it isn’t a secret.) The biggest problem I have noticed though (again more on the much older threads) was apikorsus that was in fact posted.
Then is the issue of how the halacha is affected considering the fact that for the most part everyone is anonymous to everyone else.