Not that I think this is conscious, per se, but I think part of it might be driven by the need for their school to be a "top school." It's not enough just to take AP courses and get As, the overall ranking of the school you do it at ends up affecting your admission chances. Staff might have similar concerns around funding.
That probably puts a lot of pressure on all the students to keep up the standard, probably past a level that makes sense for any diverse student body.
That probably puts a lot of pressure on all the students to keep up the standard, probably past a level that makes sense for any diverse student body.