Additionally, acting like being penetrated is an act of submission is deeply rooted in misogynistic, cisheteronormative ideas of sexual intercourse, as in "penetration is something that is done to women for the sexual gratification of the man, nothing more, therefore it is inherently degrading and feminine".
A cishet man getting pegged by his cishet girlfriend is not gay, he's not less of a man or submissive by default. A cishet man getting pegged by his cishet girlfriend can be sexually dominant and simply likes to be fucked in his ass - these two can co-exist. Yet, in the eyes of cishet society, a man that likes to have his ass played with, must enjoy it because it's "degrading" , not because it simply feels good.
That's why I so heavily preach about the difference between sub/dom/switch and bottom/top/vers. Penetration can be used to increase the feeling and severity of a power dynamic, but it doesn't create one. These two things are entirely separate from eachother, unless connected willingly.