I'm not going to claim that they literally DON'T read the private forums, I know for a fact they have or atleast Yoshi does sometimes, probably pretty quickly given him having a big job. He's liked some posts or responded a bit here and there i've heard.
It doesn't stop the fact that there's almost no mods or other team leads since Yoshi clearly can't read through the majority of posts. Going back to my point that they can either add more forum sections, or have people have a public discussion since it is a FORUM until then, since it's the most similar section people have for existing heroes.