The thing is, too, no matter how helpful, friendly, charming, delightful and wonderful any member seems to be, the issue is not about that at all, but rather specifically around whatever forum rule(s) he or she may be violating at any particular time. And, yes, in the case of some members those violations do add up after a while, certain posting patterns inevitably emerge and if there is a persistence in those regardless of reminders/cautions/warnings/temporary suspensions, etc., yes, further decisions have to be made.
At some point an administrative/moderating team on a web-based discussion forum is going to have to address the issue of how any member's posting patterns and behavior have an impact on the many, many other members of their site and eventually make a decision which is considered to be for the overall good of the community. They can't do anything about whatever may be causing this type of behavior in the first place, that is way outside their realm, they simply need to assess the situation in front of them and work from there. It's not an easy decision, nor often a popular one for various reasons, but it certainly is a difficult one for any admins/mods team to have to make and implement.