Maybe he "It's MA'AM"ed the arresting officers like he "It's MA'AM"ed and troonsplained that female officer who asked if he had a ding dong.
He probably did it from the moment the arresting officer first pulled him over, saw that he was a man, and referred to him as "sir."
There's nothing in his mugshot to even suggest Dave was trying to present as anything but a dude on the day he was arrested. While driving along, there is no way the officer could have identified him as trans, and thus targeted him for a traffic stop for that reason. Even if Dave is dumb enough to have his car plastered with bumper stickers proclaiming his degeneracy, to look at him nobody would think, "Oh, that must be the tranny all those stickers are about."
So the cop pulls him over, naturally addresses him as "sir," Dave gets shitty and whines that he's a ma'am, and then produces a driver's license with a woman's name, and Female as the sex.
In, shall we say, less-cosmopolitan parts of Tennessee, this isn't going to go over very well. It might even suggest to the cop that something shady is going on. And I rather doubt that Dave was remaining cool, calm, and collected, and came across as honest and forthright, having just been pulled over. His body language, mannerisms, and attitude no doubt gave him away as somebody with something to hide.
So he gets arrested, and during booking and being processed into the jail he got regarded and treated as a man because he is one, and any casual observer would identify him as such. But instead of thinking, "Yeah, I know exactly why they think that way, and don't believe I 'm a woman, so I'm just going to cooperate," I can totally see Dave taking the, "I am a woman! It says so on my driver's license! My genitals have nothing to do with it! This is discrimination!" and spouting a bunch of troon gooble-gobble at them.