To answer your poll I say yes. There is no reason to resort to verbal harassment or insults and the like just because you're frustrated at someone. The time you spend typing out insults is time that would have been better spent playing the actual game itself. Besides if you've been given multiple warnings and chances to clean up your act and you refuse then there's no reason to allow you to keep access to your account.
As far as int. feeding there has to be proof beyond a reasonable doubt to punish someone for it, which is why it's more common for text-based offenses to be punished as opposed to gameplay-related offenses. This doesn't mean that they never get punished (they do, with a 2-week ban as the first punishment) but it's more rare to see people complain about gameplay related bans than chat-related bans. In case you don't believe me on this point here are some examples of gameplay trolls being banned. Yes it's just a few examples, but it proves that they do get punished.