Being attacked leads to paranoid-like behavior. Your Bayesian filters go all wonky when you know they're actually out to get you.
It pollutes everything in your life; you need to be suspicious of everyone and everything.
The other thing about a constant series of attacks -- without support to field them -- is that you DO misidentify things, and sometimes respond imperfectly. There are 24 hours in a day. Sometimes you'll miss something, and other times, you'll overreact, or just react inappropriately.
Talk to anyone with a stalker.
Now imagine that stalker has a billion dollar war chest, and can hire a PI to trail you on a whim, corrupt government officials, or wield more-or-less infinite resources compared to you.
In terms of weird beliefs, we all got 'em. The difference is mostly with regards to whether others find out about them.
I haven't been in the same position as Elbakyan, but I've been in a sufficiently analogous one that I don't see what she's doing as anything other than human.