This idea crosses my head often but just imagine if the clone troopers came to earth with their African American S/O only to find out that they get treated unequally like them. People of color don’t get discriminated in space because it’s so diverse so it would come as a surprise to the troopers that people would get work up over something so petty.

Clones would be confused and mad at why there’s so much racism in Earth, but I don’t think they’d be too surprised.
Let’s not forget that there IS racism in the Star Wars universe. First of all, clones are slaves to the Republic, and they’re considered and treated less than a “normal” human, not because of their skin color but for the fact that they are clones, so they definitely know discrimination.
And not only that, but for me, the biggest example of racism in TCW is seen in the Mandalore episodes. It’s NOT a coincidence that Satine’s “perfect, peace lover” society is 99% (for not say completely) conformed by pale skin/light hair people, while the “bad ones, war lovers”, the ‘enemies’ to her government, are mostly POC. There are serious racism implications in those episodes.
And that’s only about humans. I have no doubts that there is racism between species too. For example, many consider the gungans as stupid or idiots for their way of talking and maybe for other things too, and they weren’t even considered as part of Naboo society until the end of TPM, but they had a very well established form of the government that worked for them, but were still treated as less. I highly doubt that this didn’t also happen between other species we don’t know much about.
The Star Wars universe seems like a dream to us, but let’s not forget that they have the same problems w have here on Earth, racism is one of them, as well as corruption, slavery, criminals, WARS!!!. All of that makes us realize that it’s not a perfect universe, but that’s what makes it feel so real for all of us.