Hostile yes, invincible no. Invincible is a ridiculous claim as I've had it before and gotten killed due to a persons skill. Like usual, skill will always be a deciding factor in how you decide. I agree with it being hard as a freshie to start a base and I've experienced it before, but that's more or less due to a player's sociopathic tendency to just be a douche. May I recommend moving away from people and the rad zones altogether for a good start. I don't believe they should be nerfed, and if so only slightly. As to get that far in the game to get that gear takes skill, patience and time. I play on the Australian server, and theres a legend of Esco and his friend taking on 6 people. It was a 2v6 situation and he still won and that was due to his skill and there will always be people with more skill than you.
Esco does not have "skill" while he was raiding us (which he failed at doing so) he was talking over game to his buddies and we happened to hear him say that the girl in there clan actually makes the cheats for them. mt reasoning behind this is that my group had full kevlar we poke our heads around the corner and dead instantly from a pistol. (happened multiple times) there was also a LARGE difference in accuracy when they were shooting us, when they realised we could actually kill them there accuracy went from 'Can't hit the broadside of a barn' to constant headshots while both us and them were running. -end rant