Also the person could clearly just look up gamestop's corporate number on their cell phone.
Sure. But he doesn't want to just look up the number, he wants to humiliate the clerk for insulting him.
Asking an employee for a corporate number is a part of any customer service job. Providing that number is what the employee is supposed to do, but he refuses to stop misgendering her and wasn't even making a motion for that number.
Yes he was. The video ends shortly after the clerks says he's getting the number for the customer, but the customer storms out first threatening to tell the whole LGBT community.
And he switched back to "ma'am" again. You're being disingenuous if you're trying to frame it as a clerk refusing to use preferred pronouns. He is clearly trying to, but having trouble with when the 6'+ masculine looking individual is yelling at him.
You are entirely full of shit here.
I'm not alleging anything, it's right there in the video. Everytime she's telling and screaming at him to stop its preceded by him referring to her as a male.
Because she is clearly a male and calling a male sir is second nature even in a low stress situation, much less one where you're more likely to default to the same innocuous verbiage you've been using your whole life.