I am presently researching these so-called NoSQL databases and one thing that I keep wondering is why can't all of these database still support a limited form of SQL-like language?

Almost any json document could be represented as a db table as far as I can see. Why can't I query using a common language instead of learning each of these NoSQL database's own way of doing simple stuff like returning documents of User object that have a gender field value as 'male'. In SQL, it would be something like "select * from users where gender='male". Why can't NoSQL databases support a query similar to that? Why do they require me to describe a similar request in their own unique syntax?

I sometimes get the feeling that coining a term like NoSQL is a marketing gimmick which hurts people actually trying to learn the nuanced differences but I am only getting started. Why can't we extend SQL to support "NoSQL"-specific cases instead of replacing it with nothing.

I get that a big part of SQL is joins and the philosophy of joins goes against the idea of NoSQL. The solution to that is to still accept SQL but just throw an exception when join is used with a link to educate the person on alternative implementations.