Courtesy is good in all things. The courtesy of a bar owner letting his patrons know if it is or is not a smoking establishment, for example. Nanny statism is bad news. Trans fats and sugar drinks are the next target for nanny staters. Oh, and the worst of all nanny-state trends is political correctness such as "hate speech" and "hate crimes", of course only enforced against whitey.
Laws and public information campaigns take advantage of new information and adjust to it. Tobacco used to be widely advertised as a health enhancer as one tried to do above. It is NOT yet you act as though we should still pretend that it is.
Fats and other unhealthful foods do not affect the others in the room and so are dissimiliar to tobacco use. I can stuff my face with sweets and may disgust those watching the spectacle but it does not harm them. If I light up my stoggie in a small room it can do more than just bother some people it can endanger their health.