Let's examine your thesis, that music can make you "do something" by considering the gun controller who uses the same kind of facile thinking that got us where we are today . Can guns make someone "do something"? Gun controllers like to ban guns instead of focusing on the behavior of the one pulling the trigger. No gun ever forced a holder to shoot, just like no song ever forced a listener to do (insert bad activity here). The banner of guns is a philosophical cousin of the individual who blames the song - and they are equally wrong in their reasoning.
It doesn't matter if music and the arts can flame passions. Certainly the Founders were aware of filthy art and pornography. Yet is wasn't banned in the Constitution. Indeed, getting to Heaven is grounded in personal responsibility. When I get to the gates of Heaven, I will be judged on my actions. I don't believe Jesus will let me slide on the argument that "the song made me do it." If we blame the song, then we will lose souls.
As for musicians' intent, most of the ones I know/have met are interested in paying their bills and supporting their family. Of course some of them have nefarious plans - no society is perfect. Furthermore, while some genres have a physical focus in their lyrics an increasingly large portion of rock bands eschew that focus and instead focus on society or other, less carnal themes. Regardless, let's not ban guns...we must go back to personal responsibility.
If we REALLY want to get at root causes of shooters gone wild, a more fruitful dialogue would focus on prescription meds than the arts. Further, many people are medicated because the family has been destroyed, but it is difficult for people of faith to have that talk when large swaths of the congregation are on their second spouse, and the children are all freaked out because Dad left Mom for a trophy wife again or Mom and Dad think a marriage is a simple contract that can be dissolved. The kids? "Divorce is ok. The kids' lives will be better because Mom and Dad will be happier apart." Whoever dreamt up this line of reasoning was truly demonic.
That's where we are today...the family is under siege, society welcomes divorce, and THAT selfish behavior has more likely spawned more shootings and mayhem than the arts.
I agree with your entire post except for the capitulation to tolerating sinful ideas as "Art". That selfish behavior which you describe is rationalized and justified by the "Arts" which informs popular culture. All the fine principles you mentioned, such as personal responsibility, the desirability of an intact nuclear family, etc are antithetical to our popular culture.
Guns are tools. They don't make people do anything, obviously we agree on that. Ideas and thoughts are different.
Wearing a "Born To Kill" T-shirt is an action whose idea is connected to the movie Full Metal Jacket.
Zappa's quote is shallow and unthoughtful because it assumes "Love" songs to be about people loving one another in the highest and best sense, when actually they do not. Let's not forget the context, (PMRC) which was that he wanted to be free of accountability.