Even within a school, belts/ranks are a personal thing. Even though we're held to a standard, there's wiggle room. Allow me to elaborate...
At my former school, we had a lady who was a 3rd dan. Her technique was awful. If you walked in from the street, you'd think 'who would ever give her that rank?' She had the movements memorized, but everything was just awkward and no real power behind it. It looked like she was walking through her kata. She couldn't kick much passed mid thigh height.
But after a few classes with her she was IMO what epitomizes a black belt. She was always the first one in and the last one out. She always gave it her all. She never complained nor made excuses. If told to do something 1,000 times, she'd do it and immediately ask what's next. She was a walking encyclopedia of knowledge in the art; she could easily explain everything she knew and never hesitated to help someone out. She loved helping people learn.
She put more into those 3 stripes on her belt than anyone else in the building. After spending a class or two with her, no one in their right mind would question why she earned that rank.
And she was a pretty good fighter. Not fast, not agile, but she knew when to hit you and what to hit you with within her limits. You definitely couldn't out work her.
Then there was the 4th dan who was one of the best technical MAists I've been around. 4 spinal surgeries and 2 knee surgeries later, everything is painful. And it's painful to watch. Should his 4th dan be taken away?
I guess what I'm trying to say is know the person before you criticize their rank.