They should be free to struggle and suffer to their hearts desire
That doesn't really make sense if they live in the same communities. If there's universal healthcare but it's opt-in, there will be people who opt out. Those same people will catch viruses and other diseases, not be able to go to the doctor, then show up on the same subways and airplanes as the people who take care of themselves. This means the uninsured become disease vectors.
In the same school? That's not going to achieve much.
Will that work as well as a "smoking section" and a "non-smoking section" in a restaurant? We tried that, it didn't work.