"but Jaz, how would they enforce it"
People would report you to the police for any hint of it. Whether real or imagined. You held hands with someone of the same sex. Someone started a rumor that they saw you kissing. You bought a sex toy and the vendor automatically reported you. You clicked a web page or picked up a magazine that had a different suspected deviant on it and the shop owner or internet service provider automatically reported you. You had certain mannerisms. You hung out to much with a specific friend. You seemed too close to a family member. Literally anything.
In some cases people would literally peep through windows, listen at the door, even wait across the street for your guest to come over and then call the police to kick the door down and catch the two of you in the act.
Never forget that the Stonewall riot was started by one such raid where police stormed a gay bar looking to arrest as many "sodomy" and "public indecency" suspects as possible.
That's how. By encouraging people to barge into other people's private, consensual sex lives and make reports to the authorities. By encouraging people to lay traps so unsuspecting gay people could stumble into them. By encouraging people to stalk and harass anyone who showed any sign of 'being a pervert' in the name of 'protecting neighborhoods from predators'. By weaponizing the real concern for predatory behavior against people who were engaging in consensual intimacy in a way they happened to not like.
By doing exactly what I've been continuously saying is bad behavior that has gotten countless LGBT people jailed and killed.
We're not turning this against our own community. Homophobes and transphobes have already made it plenty clear they don't care how good or respectable we are, they just want us all dead.