"Hidden Kisses" is an anti-bullying and anti-homophobia movie, which are both worthy subjects. But, the movie wasn't particularly satisfying for me because the story is over-simplified and virtually all the characters are well-worn stereotypes. IMDB lists it as a "TV Movie", so I suspect it was produced as a G-Rated "after school special" targeted at teens and young adults.
Throughout the movie, I was puzzled by the outdated attitude and homophobia the students and others overtly expressed toward the (supposedly) one and only gay student. The film is set in a large city in modern day France, not Brunei or someplace where the "sin" of being homosexual is punishable by death. The world is still not a perfect place for gay people, but we have come a long way in my lifetime (I came out in 1978). It seems particularly unrealistic to portray the student body as a monolithic anti-gay attack force against a solo gay boy who's completely without any friends, allies or moral support.
If you're willing to overlook the stereotyped characters, unrealistic portrayal of French high school students as unrelenting homophobes and the simplistic storyline, you can watch and enjoy "Hidden Kisses" for the positive gay message.