The governments in these countries are evil, not stupid. The false positive rate is too high for this to be useful at anything but a really coarse, maybe check this guy out level.

All of the countries you name bar Yemen are easily capable of rooting out and destroying their gay communities if they really wanted to. They don’t. What they want is to make sure everyone involved is very discreet. Hypocrisy is the homage vice pats to virtue etc.