Logic and rationality

I was reading about Ad Hominem which is a Logical Fallacy wherein you attack/defend the person making the proposition rather than the proposition do itself. We have all at some time or the other fallen prey to this fallacy.
What interested me was one of the examples
"Tobacco company representatives are wrong when they say smoking doesn't seriously affect your health, because they're just defending their own multi-million-dollar financial interests."
As the article also goes on to point out "It is important to note that the above argument is not irrational although it is not correct in strict logic"
I have i think always believed logic and rational to be synonyms of each other which as the above argument indicates is clearly NOT the case.
Given a choice I'd think I'd rather be logical than rational , though it is of course easier said than done