That's why they do it so stealthily, most of the time encryption isn't even mentioned. What they often do is talk about the need to "protect the children" at the responsibility of the service provider, who in order to comply would have to disable encryption on their own. It would technically remain legal, only banned de jure.

Also most average people don't know anything about encryption or backdoors, not even the meaning of those words. In their minds they have nothing to be concerned or mad about.