Having a victim mentality is dangerous because it prevents one from learning useful lessons and skills which are crucial to survive and thrive in this world.
A victim mentality makes one wear rose-tinted glasses, thus seeing everything as an oppressive force.
In reality, in today’s modern world, some of the worst oppressive things are those people do to themselves. By viewing oneself as a victim, one makes oneself miserable.
The antidote to this seems to be to view oneself as an anti-victim or as the hero. It is just a matter of changing perspective.