Smoking may or may not be a right, but I doubt that it is a constitutional right. I don't advocate this, but smoking could be criminalized without violating any "right to smoke."
I can understand the person who posted that he wouldn't allow his mother to see his kids if she had tobacco smoke on her. I had not planned to be that extreme with my kids and my mother, but I wouldn't have allowed them as babies to be in her house full of smoke, nor would I have allowed her to smoke in my house. Alas, that issue never arose, as she died of lung cancer about 7 months after my wife and I got married....