I understand the situation now, but unfortunately I don't think I can consider this to be a problem.
First, people are free to respond to anything they want. I can't tell someone to stop replying to threads that they like just because it might mean that someone else's thread won't be at the top of the page. That's not how the forums work.
Second, even if someone is maliciously doing what you claim they're doing, it would have basically zero effect.
Your threads are very popular, so any effort to "hide" them by kicking other threads above them would be completely pointless. For example, you started a thread in the Lounge about two hours ago which already has 45 replies -- that's one reply roughly every two and a half minutes.
That means that every two and a half minutes (on average) your thread was kicked back to the top of the Lounge. In order to prevent that thread from being at the top, someone would have to kick another thread or threads 45 times in two hours -- and that would be just to prevent ONE of your threads from appearing at the top of the Lounge, and even then only for about two and a half minutes. As soon as your thread gets one more reply, it's back at the top.
I understand that you are concerned about this but I'm letting you know that it's not a problem. Your threads are consistently well-liked and get a lot of replies -- it's simply not possible for someone to undermine the visibility of your threads by kicking other threads.