Rock music is often considered aggressive and arrogant and it is supposed to express e.g. defiance, party lifestyle, sexual themes, hatred or desperation. Even if rock was just about these themes, which it isn't, it is a way to handle emotions, as well as any music, and deserves credit for that. Rock has always been, and probably always will be, despised by some people. Somehow it often seems that rock music is looked down upon in public. The fact that rock music has its roots in working class doesn't mean rock can't be sophisticated.
Rock music deserves appreciation as one form of art, as well as opera or musicals.
Rock at its best can be just as great an experience as a classic music concert. It also is often thought that rock is what only young people listen to. It seems like there is a social formula of what kind of music people should listen to at certain age. If a 40-year old still likes rock music and goes to concerts, some people think he or she is a bit childish and should grow up. Aerosmith's Steven Tyler is over 50 years old and he still rocks like one would never expect from anybody at his age.