It is improper grammar to use singular "they/them"
It would be detrimental to learning to change the grammatical rules which are already in place, as students would then have to unlearn old grammar - it is more difficult to unlearn something than it is to learn something new. Therefore it is more logical to use a new set of gender-neutral pronouns.English Gender Identity LGBTQ
"They/them" is plural and that is that. To suddenly change a fundamental part of the foundation of grammar would be confusing to students and to grammarians everywhere; and if the teacher is confused, then how are the students supposed to learn?
Singular "they/them" is gaining acceptance within many scholarly circles and has already been in use for decades, and was previously in use centuries ago. It is actually the plural-only usage of the pronouns which has upset the grammatical balance. This is only an example of how language changes over time. Singular "they/them" is already a part of the natural evolution of the English language, and the change should be embraced, not stonewalled.
[P1] "They/them" is plural only, not singular.
Rejecting the premises
[Rejecting P1] Singular "they/them" is becoming more and more accepted by society and grammarians.