Minors viewing explicit material causes those ideas to be normal for them, including dangerous ideas such as what could be seen in fifty shades of gray. No minor or adult needs that in their life. We need a moral up-right society not a bunch of sex obsessed creeps everywhere. Minors should be either working on their jobs, school, or just playing, not thinking about sex.
So minors can legally have sex (with someone who is not too old or too young). But looking at sexually explicit pictures is bad and so is using sex toys? So if the real deal is okay, why are just pictures and toys bad? It makes no sense to me.
It's human nature that they always will do what they are told not to. Especially teenager when they do not have enough knowledge of safe sex. They will do whatever they can to satisfy their curious mind. And make them responsible for this legally only make it worse. They already have to be responsible for their behavior (get pregnant or mental trauma...)
Kids that are using "adult" toys and viewing "adult" material aren't having actual sexual contact and spreading sexually transmissible diseases. Parents of minors that would wish to prevent their children from doing this could simply forbid them from doing so themselves; it's not the government's place to suppress this behavior. Additionally, establishments that provide such products are in this way a service to a community.
You'll get sex offenders who only purchased a barbie doll with torn clothes. This needs to become a clearer topic; what defines a sexually explicit toy or image? What would the consequences be?
Anyway, you'll never manage to monitor google images. People can use their parents computers, and many programs suggests searches that may cause said images to pop up. And what will happen with ads? We just don't know.