Personally, for me it’s the idea that just because you don’t experience something (dysphoria, or being a gender other than what society expects of you) that doesn’t mean those experiences aren’t valid.
I get sooo tired of the response “I just don’t understand! I love being my AGAB! Why can’t you just get over it?”
I just don’t think colonialism is the cause of unrealistic beauty standard in European white people. If European nations never built a single ship capable of crossing the Mediterranean, we’d still have unrealistic beauty standards. Just look at any Ancient Greek statue (my fave, mostly linking it because it’s an amazing statue in its own right); surely those beauty standards are unrealistic as well, if anything it’s even worse because Ancient Greeks truly believed that intelligence and beauty were one. Yet those standards predate our modern definition of colonialism by a couple millennia and even predate whatever you want to call Ancient Roman-Greek cultural relations.
I could see an argument that the way white people have been setting the canonical beauty standards in entertainment/fashion/etc. puts more pressure on white people, but I don’t buy it. I know that society would make it much harder for me if I was ugly-black than ugly-white (which is racist, and in some ways colonialist) but if we lived in a parallel universe where Europe is the only continent on Earth and everyone is white I don’t believe that the beauty standards would be any better because the patriarchy would still shove people into narrow gender-normative boxes.