I'm half-Mexican, but super white-passing.
Growing up, however, my Hispanic half was easier to see at first glance.
I was proud of my heritage and was happy to be a latino at my school in a suburb of Phoenix, AZ. There really weren't as many as there should've been considering the ethnic makeup of Phoenix, and that led to a lot of bullying. I was called "wetback" more times than I can count, and was physically threatened because of my race.
As I grew up and started to look more white, the slur of choice for some people became "moistback" ("Get it, cause you're only half-wet?"). I even had friends that would "lovingly" refer to me as "wetback" and "spic" and "our Mexican". I carried that with me for years, and had to listen to people, including members of the non-Hispanic side of my family, rant and rave about illegals ruining our wonderful country.
"Hey, you do know I'm part Mexican, right?"
"Oh, yeah, but you're one of the good ones!"
This sort of experience makes it super easy to relate to other minorities that are affected by racism, but I also understand that I had it light compared to many, many others.
During my time in New York, I met three multi-racial siblings (white dad, black mom) that grew up in the Deep South. They told me stories of threats of violence, hearing the n-word thrown at them as if it's nothing, and having to walk with their mom far behind their dad during outings, hoping nobody would put 2 and 2 together.
What they experienced made my childhood seem like rainbows and happy times all around. Still, after sharing stories, they felt just as bad for me as I did for them and I realized that shared experiences, no matter their severity, make it that much easier to empathize. You don't have to understand the details of the racism minorities experience, but you better damn well understand that it's an institutional problem that everyone needs to work together to solve.