I've met a lot of cishet dudes, and Job #1 for most of them was "protect guy and straight identity at all costs".
So why would a cishet guy pretend to be queer, or an enby? I'll tell you: he wouldn't.
So if an AMAB person says they're queer, or an enby -- they are. They're not "probably" anything else. There's no likely motive, esp. in this society.
ACAB and that goes double for Gender Police in activism, who should know better.