I think it's funny to see people bitching about who's posting and who's not.
The way I see it, you can either bitch about what others are doing, or you can contribute what you like and try to steer the conversation the way you want.
You can certainly try to chase people away, some people will be chased away, others won't. You won't be able to influence who comes new to the board. Attempts to influence who posts and who doesn't is largely futile and beyond any single person's influence.
I see the mix and take it as it comes. Not everything is double rainbows and unicorn farts, but there are plenty of happy posters and plenty of grouchy fucks around.