"exercising their freedom to participate or not in the activity" ignores the externalities of their bad decisions.
Your freedom to swing your fist, et c.
Now the hospitals are full and I can't drive anywhere because there are no ICU beds should an idiot crash into me. Some freedom.
You don't have freedom to pollute the air that I use to breathe, and you don't have the freedom to get and spread a deadly virus (which, really, is a subset of polluting the air that others use to breathe).
Your freedom to swing your fist, et c.
Now the hospitals are full and I can't drive anywhere because there are no ICU beds should an idiot crash into me. Some freedom.
You don't have freedom to pollute the air that I use to breathe, and you don't have the freedom to get and spread a deadly virus (which, really, is a subset of polluting the air that others use to breathe).