If you reply to trolling posts, you are feeding it and make trolleys more exciting and have motivation to continue trolling.
That will never end. By the time someone gives up and stops responding, someone else jumps in and responds to his posts again. Even with the best intentions, some users can't be helped.
I know and the forum is big enough to have many users who will ignore or join trolling discussions. I only recommend users to do their actions individually against trollers, and that's all they can do individually. As a community, other forum members must contribute and reduce replies to trolling posts but I agree with you that it is endless. There are always shitposters who don't kind what posts or topics they are replying to. They only care of making as many posts as possible for post quota, trolling or not, it is not their concerns.