The fun thing about demonyms this is that there’s no grammatical rule for them.

It’s just kind of socially agreed upon.

Nobody from Boston would say they’re bostonite. They would say a Bostonian.

However, there are many more miltons. In the world around there are miltonians and miltonites.

People from Liverpool are liverpudlians.

People from Venice are venetian.

People from St Kitts are called kitty cats.