How? If they're end-to-end encrypted, they really can't be monitored unless there's a flaw in the encryption system. Don't trust messages to systems that aren't auditable.
Chat control will require client-side AI scanning of all messages, bypassing end-to-end encryption. Since the AI will be an unauditable blackbox, it will make it effectively illegal to have secure end-to-end encryption.
Installing open source software on phones is becoming more and more difficult. It used to be the case that bootloaders were generally unlocked or unlockable. That is no longer true, including on Android. Google is also planning on banning APKs from unregistered sources soon.
We need end-to-end encryption on phones to have reasonably convenient privacy. We can definitely lose that, and open source software won't help.
Worse, once phones are locked down desktops and laptops can be locked down as well.
If this becomes a widespread way to bypass this, wouldn't they just pass a law to make Linux usage illegal unless you install some module?
I mean, look at all the geniuses saying "I'll just use a VPN" in response to the latest ID for age verification. A week later, the law was amended to also involve VPNs.
How long until hardware vendors prevent you from installing a certified OS that is specifically not anything like linux? Before you call it a conspiracy, know that we are already there with our phones, which represent an overwhelming share of consumer compute use today.
The thing is although your exact message text is end-to-end encrypted, the messages are scanned locally on the device and information about your messages is sent out-of-band to whereever it needs to go.
This illustrates why I'm so skeptical of all these "end to end encrypted" closed source solutions like WhatsApp: yes, they're end to end encrypted so the server doesn't necessarily get to see what's going on, but what's the point in that when I can't trust the client?
Yes, it is that fascist.