my job has made me racist

For background I’m 19 and I’ve been a waiter at a restaurant for a little over a year now. Before my job I wouldn’t consider my self a racist or prejudice person. However everyday I feel myself becoming more prejudice and hateful. Now I know there’s stereotypes that black people don’t tip but I’ve never heard of this before becoming a waiter. I always give great service regardless of age, race, religion, gender etc. Even still with dozens of bad experiences I’ve had with certain people I NEVER treat my customers any differently and I STILL receive the same bullshit. It’s to the point where when I see a group of blacks come to dine in my heart just drops, because I know almost right away they are going to either stiff me or leave me an insulting tip. I’ll go over to their table to take their drink orders and rarely do they ever even look up from their menus or say hi back, or are talking OBNOXIOUSLY loud on the phone. They will run you back and fourth the stupid little shit, send shit back for no reason etc, never saying please, sorry, thank you, they just shove it in my hands saying take it back i don’t want it and it better not be on my bill. The amount of fucking entitlement, rude and aggressive behavior I’ve experienced with blacks is just unbearable. I hate it. I hate that I’m becoming somebody that myself from 2 years ago would’ve hated. I don’t get black customers very often thankfully but when I do they are always just the most demanding, entitled, wont acknowledge you the list just goes on. I know this makes me sound like a terrible person and maybe I am, I just had to get this off my chest.