You even played when Survs could be hostile? They had to decide just before first contact with marines. They had to clearly state they are hostile. As soon as they said its cool, they weren't allowed to do any funny business both planetside and shipside. And because survs aren't whitelisted, admemes can react immediately to bad players.
Surv grieffing isn't even valid argument. Its 1000000000 times easier to grieff as PFC. If you survived long enough as a surv to meet marines, then you most likely had to play this server enough to be outside of the pool of "potential grieffers".
They either said clearly they are hostile, or they were friendly, no inbetweens. Any breaking of the rules should be just ahelped and thats it.