My advisor just sent me an email saying he tried to avoid pronouns when introducing me to his class yesterday and that he is sorry if he misgendered me.

This man is Literally 80 years old so the idea that old folx can't learn and change is some bullshit.

Some folx I know off mastodon are giving him flak for just using my name and position instead of they/them pronouns in introducing me to his class.

Personally avoiding misgendering me by any means demonstrates care and respect, regardless of whether or not that means restructuring sentences to avoid pronouns.
Him actively changing his speech to be a better advisor and mentor is important whichever form that takes.