Or by people who recognize trolls and no value comments.

That's no ordinary troll. Those comments were synthesized from either a stats distribution or a human using a script. The usernames are similar (dnsjjebw & dnsjkwns), both first time posters, and there's keyword matches between the posts.

I think someone's running a chatbot experiment.

The language doesn't look reminiscent of a chatbot to me. It seems that the person made a one-off account, posted something, then thought it didn't go through and made another account and posted again.

Also, Obama is a war criminal, just like W.