They do teach philosophy at some high schools, and that is probably the strongest part of the program at the high school I know best.

http://epgy.stanford.edu/ohs/courses/core.html

One of the things that high school muffs up is not having an asynchronous online forum for the students, who are enrolled from all over the world. That's crazy that the school doesn't have a pan-school channel for interaction among all the enrolled students.