This is perhaps a declining problem, as young people in so many countries are growing up as proficient US English speakers due to heavy social media consumption, to the point that US English CAPTCHA challenges would just feel normal. I suspect there are more young people around the world now for whom "crosswalk" is more natural than "zebra" -- in my country, the latter is already a shibboleth that one is an oldie who learned UK English, now regarded here as an antiquated standard after teaching switched to US English.

Maybe we should ask Americans what a Belisha beacon is.

Also a declining problem because any recent LLM can solve them all for you. FWIW though I don’t know anyone in the UK who uses the term crosswalk, though I think most would probably understand it in context.

There are more people than only young, intelligent people who want to use the world wide web.

As mentioned somewhere else in the comments here: This is just one aspect where US American culture is being favored and forced on other people and their culture.

Yes, I know how fire hydrants look like in the USA. But this is not the point. It is about respecting other people's abilities and cultures.