It's my opinion that if you're a good PKer, you're not just good at fighting - You're consistent in your characters roleplay and behaviour so that others can interact with them in a way that suits them without worrying it's going to immediately become a matter of violence. To me, this is roleplay - Playing a character who has distinct opinions on IC things, who adjusts those opinions based on what happens and who behaves in a way that is consistent. In game events that add to the lore or bring older parts of it to the fore are what most encourages me to roleplay. Even things as small as conversation trees on new NPCs (Like the nightingales!) can be inspiring in this regard.
If you refuse to roleplay and you're just hunting for reasons to fight, then you're doing more harm than good. You end up widening the divide between roleplayers and PKers and it's simply not fun for most characters to interact with you, so they don't. To then try and push this attitude - That you should be free to PK without needing to engage in any roleplay or attempts to stay IC - just makes things worse. It's also bound to ruin the game for people who try to stay IC, when you walk into a room and immediately trample all over immersion by bringing up OOC stuff in says or on channels.
It's worth noting that HELP OOC is a thing, and it's not just shouts and the like that we should try to stay IC on. Any public channel or around anyone who tries to stay IC, please, stay IC.