This is about minors, kids, who end up getting porn on there phones/tablets by accident, while looking for something innocent.
I don't think it's anything to do with "accident". Yes, occasionally, some idiot posts some disguised link and managed to get people to click on it (I've been caught out a couple of times in slashdot posts before they started putting the domain after the link)
But mostly I suspect it's 13+ year olds going looking for porn. Which we all did. Back in my day though it was all still photography in magazines. VHS was around but I never even saw a pornographic VHS cassette, let alone watch what was on it.
One of the problems is that what is depicted in porn, especially today when video is easily accessible, is not "normal." Children are getting a distorted view of what normal relationships are about.
The solution, however, is to educate them about what normal relationships are. To teach them that porn is, for the most part, a fantasy. That within a normal sexual relationship some people do live out some fantasies and that it's OK for others to say "that's not for me" and that it's not OK to pressure others into doing things that they aren't willing to do or ready for. It's most especially not OK to use porn as an example to say "well they're doing it."
A porn block won't work. Teenage boys are going to get porn regardless of what adults try. Accept that fact and work with it instead of trying to deny it.