You can't change it from the inside. Writing a letter is a good thing (do it), but you can not make them change, and they likely won't. If you really, really want to spend time making change, you need to go to the highest level, ie. not the teachers or the directors, but whoever it is that they report to.

Probably the best thing to do: just make a site with some friends, http://dontgotoquebeqcegep.org or something, make sure it ranks above the school site (shouldn't be too hard) then move on.