I think sometimes it’s important to understand when forgetfulness crosses a line to intentional disrespect.
People who call an obviously feminine-presenting person by a male pronoun might be forgetful, but after a while that’s not very likely.
People who call a man with sideburns and a beard by a female pronoun are making their disrespect felt intentionally.
What these people are doing is saying, I don’t acknowledge your transgender life. And I’m not going to have the simple decency to just call you by the name that you chose.
Sure, we need to be patient and forgiving. But not forever.