I personally witnessed managers mock a person of color who had a disability and experienced no reprimand. I saw another coworker get bullied by other coworkers right in front of managers none the less, and get it shrugged off. I was bullied at one point in the job myself by a manager who constantly pointed out all my bad points to the team (even though I had a leading PA) and HR said he was "motivating me" and refused to do anything about it even after I confronted him and td him to stop. I got promoted to another position that was higher up and all my coworkers joined in on pulling practical jokes on the new guy. I was always going to be the "new guy" so I quit after 6 months of this fed up. I had no one to talk to about it and HR only yelled at me saying I was expected to be in this position for a year. I've never confessed this to anyone yet, but now that I'm out I don't care.
I'm reaching out because if anyone else is experiencing something similar, you are better than this and don't let the company push you around. Do what you need to do. I'm so happy I'm out. If someone else is getting bullied and it's dragging you into a depression, it's not you, it's the company. Hang in there and don't stop moving forward