You're right about biracial being mixed. But I meant the stereotypical biracial. Slightly lighter skin and sort of looser/softer curls. People making post about mixed being beautiful and only having pictures of that type of mixed.
Okay, I can get why that would be frustrating but that doesn’t make people who look “stereotypically mixed” (which is to say they look like the exotified ideal of a White/Black mix) any less mixed. Biracial people are still mixed, even the ones who are touted as the ideal. That ties back to colourism, who is viewed as “an acceptable minority” and how narrowly a person deviates from popular Eurocentric beauty standards.
I don’t happen to follow any blogs that put that kinda stuff up on my dash, but should I see posts with photosets about “beautiful mixed people” and they’re supporting and adhering to those standards, I’d post some pictures of mixed people who don’t follow those tropes which are exotifying and encourage internalized racism and gassing up the privilege of mixed people who do look like that (especially if like me, they’re light skinned with light eyes)–personally, I’ve only had cause to do that a few times since usually when I see stuff like that on my dash, someone’s already done that and I just reblog it. It might be something you can do if you’ve got the mind frame for it rather than scrolling past
I don’t think you’re wrong in being bothered/annoyed/angry that very particular features/standards are pressed upon even what mixed people should look like–it supports a lot of harmful ideals that get internalized both by people who don’t look like that and can turn into internalized racism very quickly and by people who do look like that where it can turn into an internalization of unfair privilege and contribute to factors stemming from exotification that are harmful. And maybe it was just a poor turn of phrase but “Am I right to be annoyed that a lot of people in the mixed race tag are actually biracial?” is outright saying you don’t consider biracial people mixed
Even “stereotypically looking“ biracial people are still mixed whether or not anyone likes it