The difference is that these public smoking bans have been supported by the citizenry. They're almost exclusively measures that were approved by a vote.
The FDA has had regulatory authority over lethal substances since its very inception. Furthermore, the new legislation forbids them from banning nicotine and gives them very little regulatory authority over
tobacco in general.
This is your one solid example, but it's important to remember that the Patriot Act was approved based on fear resulting from 9/11. It didn't just happen one day because some draconian government decided that it was time to wiretap citizens.