I think you’ve actually misunderstood the humour in these memes. In the vast majority of Muslim countries, multiple wives is certainly not acceptable ‘religio-culturally’ (sometimes culturally, sometimes legally). It’s permissible according to the Quran, but would absolutely be frowned upon today. The nature of these memes is actually poking fun at the fact that it is permissible, rather than producing memes around something that’s normal.
The fact that you’ve said “ it can only happen in cultures with multiple wives” — I would assume this to be completely false: it’s more likely that these memes have been produced where it’s completely culturally unacceptable — and that’s the entire joke. Perhaps this is a good analogy:
While there’s a conversation to be had about double standards between attitudes between the East and West, I don’t think it really applies here.