Reminds me of TV users willingly plugging a box into their TV that sends usage data to a statistics institute
I don’t think users knew what they were consenting to. Only a small percentage of the population know what a Certificate Authority is. And also “monitoring traffic” doesn’t carry the weight of “we are going to listen to your private conversations”.
In the same way a patient might willingly consent to some highly specific chemical treatment being replaced with another highly specific chemical - they have no idea, they rely on the doctor not to purposefully mislead them. You could put anything in those forms and most people would trust the professional is at least not allowed to defraud them.
Or maybe it's a weak, uninteresting form of social engineering, but even that's a stretch IMO
It wouldn't stop them seeing what domains the user is going to (as it's sent in plaintext because of SNI, and ECH was still a few years away).