How is a single endpoint for all queries a good idea from both front and back end perspectives? How is writing queries in the front end and exposing those queries a good idea? How is exposing the back end data structures a good idea?

GraphQL is bad. You increase transparency on the client side and decrease maintainability on the server side. It's the worst of both worlds. I don't understand how people are advocating it, but then again you know how it goes, "eat more shit, millions of flies can't be wrong"

Plus now you have to learn yet another query language.