Dont forget many of those holidays are built in snow/ice/heat index days. Notice that every time weather is bad and school is canceled, one of those holidays are canceled. Otherwize the children would be going to school into the summer, when most families try to plan holidays together, and also may make them be in a classroom in a building that isn't equipped to handle summer heat.
My children attend a school that was built in the 40s, and is not air conditioned. By late June/early July the building is barely habitable when few others are there, and unbearable when all the student body is there. Why not add airconditioning? ok, with what $? the money that was going to go towards new text books and learning equipment?
I do not think there is an excess number of holidays. Wether the child is taught as to why the day is granted, thats up to the teachers and parents. I guarentee my children know why the holidays are being celebrated.
Both my husband and I work full time too. We take turns having the holiday off with the kids, with occational grandma days. Experts say having a day every couple months keeps kids (and adults) interested, and allows for mental health days.
Some schools here in the USA have experimented with the "block" system where kids go to school basicly year round and many parents complain cause it disruped their vacation plans, and test scores were no better than the children who had a "traditional" school year.
We put a diffrent emphasis on school than Japanese too. Yes the respect aspect would be wonderful, but it's also the parent's responsability to teach their kids that too, not the schools. Japanese also doesnt emphasis the team sports as much as we do.
I guess what I would say is if you think your child should be learning more, then TEACH THEM YOURSELF. Don't expect the under funded, under staffed school systems to do your jobs. When they are off school for President's Day- read a book about the presidents, do something with your kid so they learn. Dont complain that they are off school and plop them in front of the TV.