I don't see the point of topics not being deleted if no further discussion is taking place.

They are left up for reference purposes, as well as the fact that if deleted, anyone who had posted in those threads would be docked 5 milbucks per post automatically, which would not be fair to those people who had serious posts in that thread. The threads that are locked are locked because they are veering dangerously off-course into the offensive, usually, but that doesn't make the previous posts and opinions invalid, and people can still read those opinions if they want to.

Yep.

Most of the locked topics has some good info in them.
And I have also left some of them as a warning/lesson to others.

I thinks it's a great way to learn what not to say in a forum!