Because the inspiration part I see and don't mind. Like you said, it's no crime to borrow concepts and ideas.

As far as EG and PB go, any time you have a youthful protagonist with special powers who is put in an educational situation to learn to control said powers, there's only so much you can do. Ender, Sammy, Harry Potter, Percy Jackson, etc. The similarities in that regard are unavoidable. My sister is dealing with this right now in the series she's writing.