It really isn't. In a good programming language expressing a join should be just as easy as in SQL.

> It makes zero sense to pull a bunch of records back from the db using multiple network calls to join and then filter. Let the db do its job.

Agreed that you need a way to do aggregate queries on the server, but plenty of NoSQL systems give you ways to do that. I'd far rather write a map-reduce in javascript/erlang/... than express the operation in SQL and hope that the query planner does what I think it's going to do (which ends up a bit like trying to program in Prolog - it's magic until the day it doesn't work and you then have no idea what's gone wrong or how to fix it).