No, not having it.
It doesn’t matter whether you’re “having it” or not; it doesn’t change the facts whatsoever.
First of all, who the hell has ever called somebody a “Gary Stu,”
Your fellow Rey supporter NeverarGreat, to name one of countless people:
This is a good, well reviewed book:
https://www.goodreads.com/book/show/186074.The_Name_of_the_Wind
The main character is a Gary Stu.
Discuss. Or better yet, let’s not.
I suggest you do a Google search. “Gary Stu” is even mentioned in the opening paragraph of the Wikipedia “Mary Sue” article.
and second of all, the existence of a male counterpart to the name does not change the inherent misogynistic component of the other name.
There is no “inherent misogynistic component” of the term Mary Sue. It denotes a character type. The sex of the character isn’t part of the definition. “Mary Sue” is usually used for characters of either sex, but some people prefer to apply a similar sounding, but male, name to male examples of this character type.
Just because we have gendered insults for both genders doesn’t mean that one can’t be more problematic than the other.
You’re making stuff up. It isn’t a “gendered insult” at all. Also, the most famous Mary Sue prior to Rey was Wesley Crusher from Star Trek: The Next Generation.