This is interesting to me. Back in the "Facebook is cool" days, two people from middle school friend requested and reached out to me to apologize for crappy things they'd done when we were kids. In one case, I remember the girl quite well but could not remember what she did. In the other, it was a dude who punched me in the face during a basketball game, which I definitely remembered, but it was still a weird experience, because I got a black eye, healed in a few days, and was fine. No hard feelings. Sports get emotional and kids fight. But apparently this guy had been haunted by it and by his general pattern of violent behavior for decades. He'd become a karate instructor for kids. He was like a real life version of Johnny Lawrence in Cobra Kai, atoning for his sins.
Even though I had no hard feelings and never felt bullied just because a guy hit me one time, why would I deny these people their atonement? Whether it's part of some pseudo 12 step thing or just them feeling crappy about who they used to be and trying to be better, let them. It seems wildly uncharitable to assume someone is still the same person they were 20 years ago and is trying to get in contact to resume the abuse, let alone because they want to hook up with you. Bullies tend to become bullies because their parents beat the crap out of them when they were kids. They didn't exactly have ideal childhoods. Much worse than mine. If this helps them overcome it and break the cycle of abuse, I'm all for it.