Earlier quoted context omitted.
Maybe this is due to the fact, that this is inherently undemocratic? SCOTUS ruled that mandatory vaccines are constitutional back in 1905. https://en.wikipedia.org/wiki/Jacobson_v._Massachusetts
Undemocratic does not mean unconstitutional. The Electoral College is undemocratic, yet constitutional by definition, for instance. SCOTUS itself is undemocratic yet constitutional.
The USA has always been a Representative Democracy. We elect leaders whom have the power to enact rules and laws. And this is what happened here.
Don't confuse what we have with "direct democracy".