Why does WhatsApp need to be encrypted? Why do people need to be going on to the dark web? Why do people need to be communicating using secret channels? Why are they allowed to do this?
Why are you allowed to have opaque walls in your house? That means you're hiding something, right? Must be something bad. Very bad.
You do understand the concept of privacy and freedom, despite claiming not to. You might draw the line in a different place, but you do understand that there is a line.
Even without that line, outlawing private communication has practical problems with it. Make no mistake, that is what's being proposed. Broken encyption is not encryption at all. Even if you believe that everyone who is ever authorised to spy on people will always be completely trustworthy for all of the future (a bloody silly belief, obviously, especially since it will include numerous civil servants, local council officials, etc, etc) it still won't matter because broken encryption is not encryption and anyone can read unencrypted stuff. You'd make it dangerous for some victims to ask for help because there would be no private way for them to do so. You'd make it dangerous for anyone to use any form of modern communication if someone (an abusive ex, for example) might be after them. You'd make it dangerous for anyone to provide anyone with evidence of any wrongdoing, since you'd make it impossible for them to do so privately without a face to face meeting. Assuming you'd allow people to talk to other people in person and in private. You shouldn't, since you argument applies equally well to that.