>but an advanced society would be nice and friendly and socially progressive!
That's what they always say, but why? Because you saw it on Star Trek? We have ZERO fucking idea how aliens would think or if they'd think at all. They might be something that hardly seems like life to us. You can't predict a trend accurately with only a single data point and that's all we have, life on Earth.

Personally I don't think it's worth gambling our entire existence on the likely slim chance that aliens would be nice to us.