Most of the "friend only" or password locked games are comp stomps amongst friends....they are not true MP games, but rather people simply using ICO since it can be easier/more convenient than LAN or direct connect...
As for getting booted out of games cause you are a noob, that's likely because they were skilled games and the players wanted balanced teams....or the host could have just been an ass, hard to say without knowing the host and who they let in your place...
Not all games are "no noobs"...its just that if you have 10 skilled players online at the same time, it's too hard to pass up that opportunity....