Rather than the elephant in the room that anti-vaxxer sentiment has flourished, which has put vaccine mandates in general in the crosshairs.
Like when we survey people we don't get like people who are concerned about measles, but have a libertarian streak. We get people that don't think measles is a big deal and that the measles vaccine is dangerous.
In any case too it undersells vaccine mandates. We wouldn't get the kind of coverage we have without them. It isn't too important for say the flu, but it is essential for measles.
Anti-vaxxers and disease denialism aren't new. We had them during smallpox. Smallpox eradication wouldn't have happened without mandates (we did significantly more than school and business mandates for smallpox even).