I have always seen both sides of this argument and even I'm not sure what side of the fence I fall on at times, so here's both sides of my fence.
First and foremost, these people are TEACHERS. They at least went to school for 4 years (bachelor's) and some for 6 years (master's) and many also obtain their NBCT (National Board Certified Teacher) certification. They didn't go to school all that time just to be a high school football coach. They are no different than the science teacher, the math teacher, or the language arts teacher down the hall with regards to 'why' they went to school...again, to become a TEACHER.
Now, what does make them different is they volunteer their time after school to coach a sport. Most of the time for a coaching stipend (a little extra money) and because they really enjoy the sport.
With that being said, HS football is the BIGGEST revenue generating sport for any high school, so if the coaches are good, typically the players are good, which means the fan base is good, which means the gates are good which means the school is making some serious money from the gates. Should the coaches be compensated for this? Probably so. Should they be paid a base salary MORE than the science, math or language arts teacher down the hall? No. They are a teacher first, a coach second.
The schools that are paying their 'coaches' more than fellow teachers are wrong in my opinion. Those schools are saying they value sports more than education in my opinion.
Again, compensate the coaches with performance based bonuses that are based on metrics defined by the board of education for that district, don't compensate them 'just because' they coach football.
