Am I racist?

I work in a gas station where I'm the only white person. My coworkers are all black. Everytime a customer is rude it's automatically "it's because they're racist" & they have even yelled that the customer. While I know racist assholes do come in here & make racist remarks not everyone is racist, some people are just assholes or having a bad day.

We have this super old white guy who comes in almost daily buying lottery. He's always sweet & polite to everyone. He's never made one comment that would point to him being racist in any way. He was in here yesterday & they started saying how he's probably racist because he's old & white. I spoke up & said not every white person is racist. This followed with dead silence & side eyes then I was told I can't say that because I'm white & that makes me racist. They said I'll never understand what it's like being black (which I agree with 100%) & I need to walk in their shoes.

I know racism is alive & well in America, I don't deny that. I grew up with a really racist family but I like to think I broke that cycle for me & my kids & i no longer speak to anyone on that side of my family. I also think what my coworkers are doing is wrong too because they are judging someone based solely on the color of their skin not anything they've actually done.

Am I wrong? Am I racist?

Edit: I can not possibly reply to every comment, so I'm just going to do an edit.

The people who think this is a troll post, fake, etc believe what you will but this is unfortunately 100% real.

I have no plans on reporting them or getting anyone in trouble. That's just not how I roll but I do plan on removing myself from the situation as soon as I can find a new job.

I realize I should have just not said anything but I have always stood up for others & what I think as right (my downfall, I know). If the old white guy had said or done something racist I would have stood up for my coworkers just the same. The girl who was ringing him up even told our coworkers "He's actually really nice" after she heard the conversation. So no I don't think he's done anything to anybody.