I get the personal freedom stuff, but for me paddling is also about being part of a group, and adhering to community norms.
If you are in a club or paddle with an organization like the scouts, PFD use is part of the deal. Some people prefer to stay away from these groups because of the structure, and that is their choice.
There are definitely some disciplines where PFD use is not an option. Show up for a whitewater trip in this area (I suspect any area) without proper gear, including a PFD, and the group will let you know that that’s not OK. I have done less sea kayaking, but I expect it is pretty much the same with that group. I go on canoe poling trips where we spend the entire day in water that isn’t above our knees, but everyone has a PFD on. Why? Because that is the expectation, and the community norm.
Why is it a community norm? Because in a group, everyone is responsible for everyone else, and everyone is expected to do everything that they can to keep themselves safe, like wearing a PFD. If you don’t join groups then it is not an issue.
I know that there are disciplines where the culture on PFD use is not as strong – racing is one of them. SUP’ing is another. I don’t do that type of stuff, but I assume that they deal with safety in different ways.
So I guess my bottom line is “when in Rome do as the Romans do”. When you are in a group where PFD use is the norm, put on the PFD. If not, you are on your own. Personally, I’ll always wear my PFD regardless.