The problem with the word "denormalized" is that it doesn't specify what direction to go in. It's about like trying to get to San Francisco from Chicago by driving away from New York.
A star schema or a snowflake schema is certainly not normalized. And it certainly performs better than a normalized schema in certain usage patterns. But there are cases of denormalization where the designer wasn't following any discipline at all, but just composing tables by intuition. Sometimes those efforts don't pan out.
In short, don't just denormalize. Do follow a different design discipline if you are confident of its benefits, and even if it doesn't agree with normalized design. But don't use denormalization as an excuse for haphazard design.
