People are sometimes reluctant to believe you have their best interests at heart when you force them to do something. From Jeffrey A. Tucker at brownstone.org:
The fight over the Covid vaccines has become an epic struggle. It’s not just about who should get the shot and how many shots. The fight ever more centers on issues of effectiveness and safety of the product itself.
One group is convinced they are very dangerous for many people. The other side says that the people who say this are crazy, ideologically motivated, and spreading misinformation. Truth is, they say, these vaccines saved a million lives, are perfectly safe, and everyone should accept them, by force if necessary, including a booster and a fourth dose.
You can click all over the Internet on issues of vaccine safety and find articles in both directions. There are claims and counterclaims, assertions and fact checks, fact checks on the fact checks, and all of this continues without end. Because causal inference is so extremely difficult, people believe what they want based on political biases.