George S. Ledyard
Where I am a real hard ass, and unapologetic is when it comes to the folks who are teachers. I have no patience for well meaning mediocrities who set up dojos and then become the limiting factor in the training of their students.
My guess is that they wouldn't be teaching if they didn't have a dan grade under their belt. Seems like your anger/frustration should be directed more to the those who promoted them in the first place.
Can you really blame the sandan who sucks for being deluded when some shihan somewhere gave them that rank and told them they were ready to teach in the first place?