The whole point of this legislation is to create tools to control the internet more and more. Protecting children is just an excuse, like it almost always is.
I grew up with dialup modems, so accessing this content wasn't particularly easy or quick. Today, 2 clicks and you have children (and adults) terrified at what they have seen.
The internet has changed a lot, the speed, popularity and economic prospects make it very popular for everyone. Because of this more standardized pornography controls are needed. Not only to protect children, but also to stop human trafficking and abuse.
It's a lot less easy to do so accidentally than it was 20 or so years ago, unless you are just defining “high fidelity” narrowly and are more concerned about comparatively mild but high production value content than, say, 240p video or 800x600 still bestiality, child porn, etc.