It seems people want things just to have them. All MMOs have internal test servers so opening a brand new server for the sake of "every other MMO has a public test server" is pretty pointless and a waste of resources when they have so much more to worry about.
Only they don't have more to worry about. Nothing is more important than popular opinion of their product. And much like Beta tests (And what XIV did with Beta testing) you want to be able to increase build up for your product. I understand people are playing for free right now, but playing future builds gets more people hooked than you obviously realize. I doubt it happens honestly, but that's why it's important anyhow.

Before you go jumping on people you can't assume everyone is native English speaking and know the nuances of the language, but as you say...
Yes. Yes I can. If I'm on an English board, I am going to assume everyone can speak English well enough to understand hinted things and slang. I think you speak Japanese natively? If I was on a Japanese board and I missed a reference or misunderstood something, I would hardly blame you for my lack of knowledge on the language. It would be my fault entirely.