This behavior is just a fact in business. Not an opinion.
There are exceptions of course, but exceptions don´t reflect the standard.

"I never said tell the whole story, but he hasnt even said what genre the game is."

It´s just offending to dictate such "peanuts" to a possible customer. Insteat you should be curious about his project.

To often possible customers are offended whe they read such posts. They even don´t get any serious answers!

If you are the only person that answers, it could be the beginning of a very good business.
If I had the time, I would ask him for further information.

Btw.: I make my life from such "vague" jobposts.