I don't see a problem feeling grossed out by some strangers long nails going into the food area of your plate. It doesn't matter that the server was possibly gay and a black BLM supporter. It's not racist to listen to your own mind about how a situation makes you feel. I stand against racism and discrimination of someone's lifestyle choice so if I see it then I call it out. In this case it's just as you have stated, gross.

Fortunately we live in a more tolerant time and don't want to come across as a racist or homophopic. Unfortunately this cuts both ways. You're having to tolerate something else to prevent a misunderstanding and at the expense of enjoying your dinner. Congrats on being morally strong and considerate of someone's feelings. I think part of having a clear conscience is being able to say something bothers you when you know it's ok to feel that way and you know you can do say something tactfully to fix the problem.

In this situation I would have quietly spoken to the manager and left. The reason I would have left is that I would wonder if the server spit in my food after I said something to the manager lol. I'm sure he wouldn't do that but that's what I would be thinking. The meal is ruined either way so why put myself through it.

I did eat at a fast food restaurant and the young man at the register had long painted finger nails. I wasn't expecting this when I handed him my money. He seemed very shy and fragile so I said hey man nice finger nails. He smiled and said thanks. If he was my son I would want the world to be nice to him too.