When it comes to vaccines, there is no true "mandatory". If you don't like it, you can run and hide, immigrate to a country without vaccination requirements, lie/forge your vaccination status or find some way to function outside of society. If you honestly believed that vaccines caused autism, you would do everything in your power to escape being inoculated. But few people go to this extent, even after the myth was debunked, because it's not actually about vaccines.
It's not about fluoridated water, or about climate change either. It's about uneducated, right-wing leaning voters believing in a mass conspiracy - leftist, capitalist, governmental or otherwise - and conservative politicians using that rhetoric to terrify and manipulate them. I worked in a public hospital and there is deep political, cultural distrust toward the government. This distrust actually has roots going as far back as the founding of the United States, which was always against concentrated national power.
Ultimately, vaccines are a final line of defense against disease epidemics, with the ideal status quo where the risk of contracting a disease from the vaccination exceeds the risk of catching it in the environment. This is the case with smallpox, which is extinct now that the vaccine stocks have been destroyed. As they say in the military, it's not about you.