It being Tumblr, this meme gets called out as heteronormative (Oh Tumblr! Never change!) because the caller-out is a woman who mostly leads but is in one of those rare scenes where there are too many guys (who also mainly lead), and doesn’t like the implication that it’s rude to turn them down when they ask her to follow.
Is there such an implication? Only if the caller-out then goes on to dance that song. The etiquette (and the meme) does not say it’s rude to turn people down. But it does seem like there’s room for some improvement here.
Core Etiquette Addendum 1
Erratum
There is a further bit of etiquette (not so far referenced in any image macros, as far as I know) which just plain says its rude to turn people down. I agree that this is problematic (as we say on Tumblr). I think it’s usually propagated by dancing teachers in an effort to make dancing more friendly and less cliquey, but you shouldn’t be made to feel guilty for refusing extended physical contact with people you don’t want to have that contact with. The etiquette is exploitable (as we say on 4Chan) by bad actors: see this educational video (Tumblr users: trigger warning for satire).
I cast Summon Shitstorm!
There is a wider question of why it is that men usually lead and women usually follow and whether this is a good thing, but again, Lloyd sorted that out a while ago, so there’s probably no more room for debate about it, I’d’ve thought.
The rather wonderful James Sherwood outlines an alternative method here, which may be more effective for use on the hard-of-thinking, if mildly NSFW.