It's already been mentioned that it is the paper's right. I get that. It's also been mentioned that you can give a false name and address to register. Seems pointless.
The most recent editorial posted ("Facing Layoffs") could have started with comments allowed only by registered posters. Instead, it is opened to all and then it later is closed to non-registered posters, in this case presumably because it does not support the views of the editor.
What is the point? What is it the paper is trying to accomplish? Does the owner know this is occurring?