There are also some quite sinister undertones that could be read into that, whether it was intentional or not.

I think it's very intentional. As hackneyed as the phrase is, the current political atmosphere has seen this rise of demographics change as a feared thing.

Yes, my personal interpretation of it is that it is a dogwhistle, but I was being charitable. Then again, a good dogwhistle is plausibly deniable as inoccuous.

Which really make me reconsider everything this person might have chosen to share on this site, and how "newsworthy" it really is.