<human>: I'm definitely quitting, but I'm wondering if I can do anything about this.

I've worked at a pizza place for two years. 
Some events:
Two guys intentionally used the "N" word to harass a girl with black siblings. Only one written up I believe.
A guy yelled "Fuck this!!" with a room full of customers and ditched work. I wrote him up since I was in charge but I don't think it went through. 
Another guy had threatened me and called me a bitch at work, (we used to be friends but a lot of bad things happened) he just had a talk with an owner. 

On Halloween I worked my ass off for five hours straight and as soon as it died down I sat down for a minute and was ridiculed. 
A new lady who runs the store for the owner acts nice to my face but tries to get people to work all my shifts because I'm a bad closing supervisor, but until two weeks ago I hadn't of closed since December. She's been there since May. 
She told the owners to meet with me and talk last Saturday but didn't inform me, so when I obviously didn't show up one of the owners crossed out my shifts and I now can only work once a week. 

When I talked to an owner he told me that "I've caused trouble recently" and mentioned when I reporting that coworker for calling me names and threatening me.

Coworkers say I've always had unfair treatment. 
I'm the only homosexual at my work place.

Give me the gist of the text in a nutshell
<bot>: My work place is always on my case and I'm the only person who gets punished for anything and I'm homosexual. What can I do?