The very same happens in French. The use of recently popular gender-neutral structures like “étudiant.e.s” is strongly discouraged in formal writing. The older “étudiant(e)s” less so but still not recommended.
What’s recommended is to either say “étudiants et étudiantes” or just use the masculine form as a group for both masculine and feminine forms, as has been the standard forever, and almost no one bats an eye at.
It’s not TERF, it’s not misogynistic, it’s just to make texts easier to read. It takes more time and effort to read a text full of those extra period/parenthesis characters, for very very little gain.
People wanting to write a text where they consider the sacrifice in readability worth it for the extra emphasis on gender inclusion still can; the police won’t show up. It’s just not standard grammar.