The servers should be joinable, sometimes there is a bug involving Steam Networking and bots which prevent this from happening rarely. I'm looking into a fix, but you should be able to connect directly to the server IP in this case.
That's not really an issue as in a bug, but there just aren't many players playing, we need to get this mod more popular so more people can be playing it. I'm sorry you didn't get to play a match with players, but thank you for trying it out!
