I'm not a parent, but do you think that is acceptable behavior? (Regardless of the product, service, or situation.)

I can't imagine wanting to be the teacher or classmate of said 11 year old if he/she is always "bitching" about stuff. And if that behavior continues into adulthood, I can't imagine being the boss or coworker of him/her. Such negative social qualities might be detrimental to his/her professional success and social well-being.

I wouldn't be able to say for certain until I have kids, but it might be beneficial to teach your 11 year old how to tactfully and constructively discuss the negative aspects of something rather than just "bitching" about it.