SST is (one of?) the oldest of such servers, and as such defines the whole group. It also has very vocal supporters.
And its those supporters that give it a bad name. They go to other servers and complain there are only 100 BP, and they feed as they are not familiar with playing on a server where there aren't 10 players in range at all times. If the players have skill is up for debate, but they have no skill in playing on normal servers.
The other annoyance is SST has a tradition of grenading your own base, and not caring about hurting team-mates. They then take this attitude to other servers and start hurling insults at the other players, and no being useful to there team. This wouldn't be a big issue, were it not for the fact that a large amount of new players start on SST. If they drop all the shit in front of there name, then I wont care. As it is they are deliberately damaging the tremulous community, and, in my opinion, this is unforgivable.