That can't be it. There are not that many valve servers.
http://en.reddit.com/r/tf2/comments/1ttbgu/where_are_all_the_valve_servers_going/
I'm not at my computer so I can't check recently. But if valve feels threatened that communities servers are getting popular than that's just stupid. They shouldn't of removed most of their servers that forced other people to find non valve servers to begin with.
If they don't like certain communities like killstreak, they should blacklist them from quickplay. Problem is people can easily change their information and valve is too lazy to keep an eye on it.