Anecdotal evidence from France and UK doesn't agree with "isn't generally true outside of the US". When a diverse group of people is involved it's way more likely to use WhatsApp (or Signal to a lesser extent) outside the US, but iMessage is still used a lot IME.
I don't think it's a new form of discrimination either, brand awareness and social position via brands is incredibly prevalent in teenagers and has been for a while.
I don't think it's a new form of discrimination either, brand awareness and social position via brands is incredibly prevalent in teenagers and has been for a while.