Because NPR dislikes polymarket and thinks that reporting this will discredit them.

If the facts themselves discredit Polymarket, NPR doesn't have to like or dislike them. Polymarket made itself newsworthy, it can't complain if someone looks at them closely.

It does.

is it not true? from my perspective they're just stating a fact that some people may not be aware of (registering a business in a location it doesn't physically exist in)