Fun for those who are killing everything maybe, but when you are low level player and have no way to fight back, and also you stop one our most important resources it is not fun at all.
I don't mind being killed in random encounters, stolen from, bombed, but I think there should be areas where people can mine at least basic stuff without getting shot at.
The guards are there for a reason, it just happens that they are pretty shit ai at the moment that can't compete with player gangs.