James Talarico is a cis man. Not trans. Stephen Miller was intending to A) suggest that he looks like a biological woman dressing as a man, meant to be an macho insult, and B) probably mislead Trump’s idiot base into actually believing that to be true so they automatically hate him. Stephen Miller is a literal nazi in all but (maybe) name, and he hates anyone that is not white, not straight, not cis, not biologically male, or not pro fascism. If you are any of those things, he believes suggesting that you are other of those things to be inherently an insult. Whether or not you consider being trans bad, he does, and so him saying it is still an insult, particularly where it’s not remotely true.