I've never heard anyone attempt to debate whether trans people exist, so the meme seems a bit weird.
The 'debate' seems to fall into two camps. Those who question the relationship to biological sex (sports, restrooms, prisons, etc), and those who label all such people as 'deviant' in some way (usually on pseudo-religious grounds or some other spurious right-wing nonsense).
It's pointless conflating the two, they're completely different debates for completely different reason with completely different (often vehemently opposed) groups. And it's pointless pretending either are denying trans people's existence.
If you've got a set of negative beliefs you need to fight against in society you need to actually address those beliefs, not some belief that sounds bad but nobody actually has.
A few dozen is smaller than millions. It's not minimising, its maths.