To stick with the pepe example: It only works as a dogwhistle now because everyone but Frog Twitter has stopped using it. If the rest of the world had shrugged and kept using it, then it wouldn't be a political symbol now.

I think this is the same mechanism as in the euphemism treadmill[1], where it's not clear if it's better to avoid a word or to double down on it (but in a proud/positive way). There doesn't seem to be a consensus about how to deal with the euphemism treadmill either.

[1] https://rationalwiki.org/wiki/Euphemism#Euphemism_treadmill