> Who, exactly, is so strongly motivated to make such legislation?

For the part that Denmark is playing, I think the answer is somewhat readily found in the current national politics of Denmark. We've just had a pretty prominent politician 7 years ago get convicted of being in possession of CSAM. I think that's very personally offensive to our current prime minister. That has to be viewed along with her personal view of herself as the "children's prime minister", to make it into a double whammy.

We've also been dealing an inability of the police to investigate some crime, and the investigative committee established to figure out what to do about it recommended an ability for police to more readily be able to investigate digital material. I imagine the current policymakers imagine Chat Control to play a part of enabling that at a national level.

> We've just had a pretty prominent politician 7 years ago get convicted of being in possession of CSAM.

I don't disagree with your overall thesis about Danish politics at the moment, but... I think it's interesting that politicians are exempt from these monitoring schemes. So it wouldn't have prevented that guy from doing what he did. IIRC, Law Enforcement is also exempt, and they never get up to any of that, no sirree...

ANY time any legislation comes with exemptions for the people in power (legislature and law enforcement) you know it's time for extreme skepticism.

EDIT: It's just the inanity of it that has me despairing. Lobbyism at its finest (see my other comment).

Danish dude here.

We had a number of cases in Denmark over the recent years which pushes this agenda:

In addition to the obvious child abuse, there have been a case where video of a high-school girls private sexual activities where spread wildly on asocial media, fake-porn of various public figures and several cases of organized crime using various end-to-end encrypted services.

None of the Danish politicians I have communicated with like the ChatControl proposal very much, but there is nothing else on the table, which isn't much worse in terms of privacy invasion, so their only choice is ChatControl or doing nothing.

My personal opinion:

No human right is absolute, not even the right to life itself.

The demands of upholding the civilized society limit all human rights, and this limitation has always included intrusions of privacy in order to solve crimes.

I far prefer Dan Geer's proposal (See his black-hat keynote):

Companies on the Internet get to choose one of these two business models:

A) Common-carrier. Handles all content as opaque data, makes no decisions about what users see. No responsibility for the legality of the content. (= how telephone companies and postal carriers are regulated)

B) Information provider: 100% responsible for all content, no matter where they got it from. (= how newspapers are regulated)

The current "the algorithm did it" excuse for making illegal material go viral, to maximize profits, is incompatible with a civilized society.

I've asked the politicians whey they do not do that and the answers is "We do not want to piss off USA", in recent months that concern seems to be fading.

Ah yes, "protecting the children". Meme driven politics.