Yes - it's not the same as saying that no regulation is justified. But taking away people's freedom is a real cost.
It is all justified. People can justify anything.
Justification isn't the same as rationalization.
Actually, they are pretty close. It really seems to be a matter of majority.
We can stipulate definitions however we want, but the generally accepted meaning of "X is justified in doing Y" is "X has sufficiently good reason to do Y." Reasons are generally independent of opinions. In some cases, that a majority believes doing Y is justified is itself all the justification needed (a good enough reason to do Y), such as when the leader of a legislative body enforces an otherwise-arbitrary rule of order that exists because it has the support of the majority in the body, but more often, a majority's belief doesn't give reasons.