I've also been surprised by the community that surrounds TF2. People are usually pretty nice about answering questions over chat, as opposed to Xbox Live where all communication comes in the form of racial slurs.
I think this is a byproduct of the demographic differences between console gaming and PC gaming. Console gamers tend to be younger (and thus less mature) than PC gamers because consoles are cheaper (the parents are paying) and more locked down (parents again).
I'm hoping that the fact that TF2 is free now isn't enough to cause a large enough demographic shift to ruin the online multiplayer experience.
It also wasn't too hard to find servers with good a "culture" where there were so many well behaved regulars it didn't really matter.
I got TF2 for free years ago with a motherboard, and I had never played an online game before. After playing for an hour or so, I decided I didn't like it, and that was that. Then a group of people started playing it at lunch at work, so I figured I would join in and that was the end of my free time...
My name is MetallicCloud, and I'm a TF2 addict.
Check the official TF2 forums and you’ll see reports of admins relentlessly banning F2P players or regular players starting landslide votekicks towards them—though this will subside after a while, same thing happened to people who bought the first items in the Mann Co. Store and those that wore the halo lament hat.