I find the concept of ethnicity to be weird and fuzzy at best. Like, even within my own country there’s a whole bunch of different cultural sub-divisions (not talking about the russian army, obviously). West of Ukraine almost speaks a completely different language from Kyiv residents and might have more in common with Poles or Hungarians in terms of cultural background.

I think it’s absolutely valid to claim Internet as your cultural background, but the label of “ethnicity” is not defined well enough to use it that way and people love to argue semantics.