It is because the garage story is stupid but I will try to respond. Oh course sitting in the garage with an engine running is worse than cigarette smoke. I can't remember the last time I sat in a restaurant with a car engine running. Sitting in a garage with a pile of burning tires is worse than cigarette smoke too but haven't done that in quite a while either. See how stupid that is? ;9}
You are missing the point of the garage story.
The point is that one hour of exposure to tobacco smoke in a bar or restaurant is no where near as deadly to a person with no pre-existing health issues as is exposure to automobile exhaust.
The entire point is that it is a matter of choice as to which place you wish to enter.