The game will still have multiplayer at the start it just won't have any kind of leagues. And really, if someone can't enjoy a game unless total strangers are aware of how good they are at playing it, then I really don't have a high value on that someone's opinion. Yeah, bragging rights are fun, but what's the point if you don't enjoy the game? "I can scrape manure off a barn floor faster than 90% of all barn owners!"
As for linux, I do think HBS made the right decision. They can either make 100% of their backers(and potential future buyers) wait, or they can make 25% of them wait. And I think saying 25% is a little generous. Of course, if I were a Linux user I'd still be pissed, but I think I'd understand HBS' motivation for the decision.