You know these threads always end up being "MY kid does 15 hours a day of school work, tutors little kids for 2 hours a day and goes to cheer camp 6 hours a day" I always read it and add--". . . and walks 10 miles to school . . . in the snow. . . barefoot. . . uphill. . . both ways.
Some kids need a break in the summer. Some kids will simply burn out if they continue being stretched to the limit with the amount of work they are given.
AP classes may be invaluable to some, but that doesn't mean it has to be to all. If a parent or student is not willing to give up the family time that summer can bring for these classes, then the student shouldn't take them without feeling like a slacker.
I completely agree with with you and said the same thing earlier in the thread. Everybody's priorities are different. Not everybody wants or needs to take AP classes. I know plenty of kids that go on to be successful without taking a single AP course. It all depends on what the kids are shooting for.
However, the OP was asking if the amount of work his daughter was assigned was normal, and the classes he was asking about were AP and/or honors classes. So, people were answering that yes, that is typical of AP classes.
The only reason my kids are taking AP classes, not because they are some big honors kid (far from it), but because they are also dual enrollment with the local university, which is where they want to go. My other kid did it and walked into school as a sophomore, saving a ton by skipping the freshman year. They can take all their "extra classes" in high school and get those out of the way. None of my kids have ever taken the actual AP tests, so I have no idea how they would have done.