[sltkr]

Network layer blocking is almost never in the interest of the end user. It's typically used to block users from accessing sites they want to visit, like The Pirate Bay, or recently Russian Times and Sputnik News.

End users who want to protect themselves can easily install blacklists on their end. All major browsers support something like Google Safe Browsing out of the box, and these blacklists are more likely to be kept up-to-date than those of the average ISP.