It's a regular request and a search should provide our previously stated reasons for not allowing off-topic posts. It basically comes down to the fact that this is a firearms board. We desire to keep it that way.
I've closed more than my share of late and I do understand your frustration with some of those decisions. But you're still a relatively new member and wouldn't necessarily remember the days of 1998-2002. Back then we all understood that this site was not just about firearms but about responsible firearms ownership. We often looked at threads from the viewpoint of the fence sitters and asked, "Does this really show us in the proper light".
And so it is that, of late, I've closed threads that make us appear as bigots....most are not; I've closed threads that make us appear as trigger happy white trash....very few are; and I've closed threads that make us appear as an inarticulate anti-social mob.
These are my calls to make in those forums that I moderate. They will never be popular, but someone has to make those calls to the best of their ability.