The smoker is de facto responsible.

Then why do companies need to spend enormous sums on advertising and marketing?

Those are not responsibility in the de facto sense.

You seem to suggest there is no de facto responsibility for lying.

someone sells a car to a person that commits a crime using it; the car seller is not involved in the planning or execution of the crime

A mob boss throws one of his cronies the keys to his car. "If my rival ends up dead tomorrow, the car is yours. By the way, he's going to be at the corner of 5th and Main tomorrow."

But he's not de facto responsible, because he contracted a third party to handle the dirty work.

The tragedy of the commons is not a purposeful result

The tragedy of the commons is a foreseeable consequence of individual actions.

You can see this play out in a game of Jenga. Everyone is pulling blocks out of the base of the tower. Asserting that the last person to pull a block is "de facto responsible" neglects culpability of each of the other participants.