I feel the same way about a smoking. I'm opposed to both smoking and a ban on smoking. It's not because I don't think an effective ban would be healthful, but because I believe that the concentrated power needed for it is a greater danger. It's the same argument that I believe supports the first amendment: people saying evil shitty false things is a lesser evil than the power needed to stop them from saying them.
And suppose no one banned smoking, and smoking was still allowed on airplanes and most restaurants had smoking sections would we be better off? I’m sure all the people who died of throat cancer would tell you otherwise.