Dear fellow tech people, why do people bully? When the victims have overcome it, how did they thwart their bullies?

It’s ridiculous. I remember being bullied in a lab once for being an “outside” major than the lab. I left the class within the drop period. I’ve also suffered professional bullying at a workplace. The experience still haunts me and will for a long time. Luckily I could move out of state and industry.