Falselogic-
You're probably not being ignored, but rather the people you're talking to aren't signed in and won't see what you're saying until the next time they play. You'll find that especially as a beginner, much of the game takes place while you're not there.
I've actually found that most people are friendlier than those who occupy the average online game. Plenty of people have given me advice as a newbie, and when I've run into groups they've always offered their hospitality, even when I tell them I'm not interested in joining them.
Though I can't say for sure why people act so nice, I guess it's partly because even talking takes up precious energy, so it's pointless to waste too much of it on vitriol. Also, it's possible the truly malicious players have decided to be zombies, and they can only speak with a limited vocabulary (though there are a few human teamkiller groups).