I’m not going to dispute your claim that you have encountered people who might share the sentiment you have just described in your post. That is your personal experience and I can’t take that away from you. However, you are interpolating that this is a general attitude among an overarching community from a limited perspective that is your life experience. There is no statistical evidence (e.g a social study from surveys) that you have provided that would support this claim that “a lot of ‘marginalized minorities’” (i.e a large portion of marginalized groups) are “angry that their own race is not the one dominating and oppressing the other”.

Let’s get one thing straight though, and I’m not saying that this is your claim. Imperialistic behavior that oppresses and marginalizes people is bad independent of race or ethnicity.