While I do agree with you (as in they would be better suited with a group), their thread violates no rules. It is a thread about a site for grifball in the grifball forum. It's also a site that helps the AGLA. I see no harm in the thread and people don't need to read it.
It makes more sense than a lot of threads in there.
Even if you were, posting in that thread won't do anything but cause trouble, and you know that. Next time, if you have a problem with a thread existing, bring it up to a forum mod.