However, trolling isn't allowed. If a user is habitually posting obviously false nonsense ("obviously false nonsense" to an outsider, NOT to someone who follows or is involved in the discussion) just to stir up trouble, then it's considered trolling, which is prohibited. Such cases should be thoroughly documented in the report though (There are tons of reports that just say "trolling", but moderators don't have time to look through each user's post).

Q: Someone insulted me. Why aren't you deleting his post/thread?
A: Possible (since we don't have the time or resources to check) insults are also allowed as long as they contain any kind of constructive opinion, info or something else substantial and aren't off-topic. For example, posting something like "you are dumb" will be deleted as it contains no meaningful content. However, if the post is somewhere along the lines of "You are dumb. This is wrong because this website/thread/etc. has explained it's not right", it's in most cases accepted.

I said, I announced that I am now a Bitcoin Ambasador. How did you bully me about it ?  Unless I have capacity and capability, I would not speak it at all. Now please understand, that a gold Smith has a plan  what he is going to make with gold ?