My high school was extremely competitive. Teachers graded f, d-,d,c-,c,b-,b,90,91,92,93, etc.to 100.
There were classes that ran from b to 98 or higher. Why not?
If the school is too tight on grades, then potential grad school applicants will have to flood the easy courses or be out-competed not only by their classmates by by foreign gad school applicants.
Unbelievable, your logic escapes me but that may be because of the generation that I came from.