I'm friends with several philosophers since I took it fairly seriously in undergrad and befriended several grad students. From my perspective, the "trolling" is generally just pointing out interesting entailments of another philosopher's arguments. For example, in a recent thread philosopher X outlined philosopher Y's argument just to point out that he hopes it shows the "weird consequences" of the basis of Y's argument. Y showed up to point out that X had missed a key wrinkle. A bunch of others showed up to wrangle about the meaning of certain words.

... So basically the same thing philosophers do in their papers, just with fewer citations.

(That's not me throwing shade -- just pointing out how the field seems to work. I loved and still love philosophy.)