I don't think anybody is going around discussing the philosophy of government because they're concerned that they aren't free enough to be advertised to.

There is a marked difference between governments interfering with an individual's freedom to act on themselves and interfering with an individual's freedom to manipulate the actions of others.

>giving mega corporations carte blanche to market poisonous and addictive substance

They absolutely do not have this. Tobacco ads are banned from TV and Radio in the US, for example. Wouldn't exactly call that a blank check.

https://en.wikipedia.org/wiki/Public_Health_Cigarette_Smokin...