You’re absolutely right, that this guy deserves a fresh start. but the OP also deserves - and has a right- to work in a place they presumably feel safe. If I were the OP… my response would be to bring this up with HR; document every interaction with this guy while also actively avoiding interaction with him as much as reasonably possible, and most importantly shut the fuck up about it.
HR can assist with avoiding him, if that’s reasonable. (opposite shifts, putting out at opposite ends of the facility, or in places where they’re unlikely to cross paths, etc.). But ultimately, the guy deserves a fresh break and OP deserves a place they can feel safe. but if its a one-or-the-other, OP needs to understand; they already hired both of you, so from a business standpoint, that decision is going to come down to… whose loss would be less detrimental to the company’s profits.
Terminating the guy simply because she’s uncomfortable and he’s a convicted rapist… is, unfortunately easily defended in court. If he’s also exhibiting patterns of behavior that suggest he’s not reformed… (catcalling. derogatory/misogynistic remarks.) it’s even easier.
But the other side of that is too: Terminating OP because she harassed a guy is… also easily defended in court.
the company will fire whoever impacts their profit margin the least.