I really dislike the instances of inter-forum stalking that occasionally occur. I noticed one member doing this in the past couple of days, following another member to new topics to continue abusive (an unprovoked) personal attacks.
This has happened to me twice in the past, from 2 different members; one was eventually banned for it and the other backed off after being reported. I just choose never to engage with that member now.
It's a nasty thing to do, and isn't always evident to the mods unless reports are made. It should be added to the 'rules of conduct' I think; otherwise it could have the unhappy result that the harrassed members leave and the abusive members stay on to abuse new targets.
Of course we will all have times when a member responds to a post in a way we don't like. But that's just part of forum life. Most of us just let it go (except on PPR, which is known for that). When it happens in other forums, it's more unpleasant somehow. I'm sorry this happened to you. I think forum stalking is a form of trolling, personally.