Without intonation, it is difficult to be sure, but this comes across as if you are scoffing rather than asking. If this is the case, and your mind is made up, then please disregard this. If you are asking however...

Two drug related offenses does not an addict make - any more than zero drug related offenses mean that someone doesn't have a problem with drugs. It could simply be that he enjoys smoking pot - thinks that the laws against marijuana are unfair and arbitrary (i.e. legal on this side of an imaginary line between states - and illegal on the other side), and has little respect for authority.

As for the lying...well, I've told my doctor that I've quit smoking cigarettes in spite of the fact that I haven't simply because I am tired of listening to him telling me I should quit. It is my choice to smoke and the cost is already high enough without tacking on a speech every two weeks to the cost.