Conservative values tend toward personal responsibility, hard work, patriotism, loyalty self sacrifice...basically adult behavior. Rock music's message (when there is one)is basically rebellion against all of these (while Country music embraces them). Politically it's liberal vs. conservative philosophies.
However, Rock has been around since the 1950s. A newer generation may rebel against status quo liberal philosophy and see that reflected in their new Rock.
Just generalizations. Do not believe popular music has the impact it did a generation ago. And there is so much great Rock from so many years that one should just enjoy listening to what he likes.
Personal responsibility