It's not really an abrupt change. He's been this way since the beginning. There was a few months in the middle where it was toned down is all.
@DisneyCane has been very consistent that it's a personal problem to protect oneself. That the vaccine is the best way to protect oneself. That if someone doesn't or cannot get vaccinated, it's on them to protect themselves. That each person should make their own decision about accepting different risks and take their own precautions to mitigate personally based on their own personal risk tolerance. That as a personal decision, there should be no mandates at all.
The problem has always been, that while vaccines do help the individual, they're really a population solution first. It's a group project not an individual one. We need the group to solve the pandemic not just distinct individuals. This has been explained by many people many times throughout this thread, yet it never sinks in for several people. Nobody likes that we're dependent on the group, especially when they disagree with a large portion of the group on many things.
I don't expect it to sink in this time either. I can probably even predict someone will respond with "Even if the US group vaccinates enough, the world never will so the group that is everyone will never get there". But, you have to start somewhere. We started somewhere with smallpox, measles, and polio. Everywhere isn't done yet for all of them either.
So we have the group of "it's personal" railing against any "it's the group" actions which unfortunately will delay how long it takes the group to solve the problem. It's kind of ironic that the individuals that want it to end the most are actively causing it to take longer.