Yeah it sounds like this guy is the type that thinks a critique means outright criticism. There's a difference, but a lot of really younger artists don't really see that.
Personally I had a teacher who once told me my art was generic and pedestrian--but that was a totally different situation, that was a teacher who was actively trying to help me reach my goals and find work in a very bloated industry, and someone who knew where my goals were, and how to reach them because he was already where I wanted to be. In my case I had to hit the books and really study anatomy and get more serious about my medium in order to change my style to better suit it's artistic purpose. He told me harsh critisism in that case because he had known me several years, and knew how I would take it, and knew how serious I was about being professional. He wouldn't just dunk that on a first year, youknow?
But in this case it sounds like they're just saying generic, not because they know what generic even "is" but because they don't like it and have no idea why. In the case of a teacher who can critique, they can give you advice to help you change that actually means something because they have professional experience. This person can't really give you any explanation, it sounds like, so we don't have any idea what they meant. They might not even know what they meant.