I don’t think it was great reffing, I think it was silly and not needed. That being said, I don’t necessarily think he was wrong within the rules if that makes any sense.
I suppose being the age I am, I’ve always been a bit of an Arsenal sympathiser as back in the late 90’s they were the only ones capable of beating United. But I think I’d call it the same if it were any other team… barring United. Then it’s a definite red!