Haha, yeah i've had that aswell, man. I've never even played DOTA as i held firm that custom games were retarded.
But since this is a standalone game, i guess it's okay.
The first time i joined a Noobs only game and i wasn't really sure what the hell was going on so people started flaming aswell. So i told them to look at the god damn game title and either help or keep their mouths shut. So they started helping me ;d
Good thing my 2 brothers own at this game so they give some good advice and walkthroughs. I used to play a shitload of Starcraft so the micro and such is pretty decent still, thankfully.