@scalextrix
Nah, that's no excuse for being this kind of nasty.

My guess is she is someone who was constantly filing frivolous complaints about her superiors and coworkers, ended up getting fired. Then she ended up suing for some weird thing like sexual harassment or racial discrimination, then got her job back as a condition of not furthering her suit.

Another possibility is she is a nepotism hire. Being a support program for people with disabilities the most likely reason the company exists is some politician is diverting money from a govt program to their own pocket and using the place as their own personal piggy bank. When that happens usually there is someone who no matter how nasty they are, are just "unfirable". You come to find out it's because they are well connected socially.

Possibly both.