Yep.
The funny thing about it though, some of these drug warrior types always use the danger of the drug itself as their main reason for wanting to keep them illegal, so by Penn saying he never used before they pull out the "well, he aint never used drugs before, so he has no idea what he's talking about when he says he wants to legalize them." argument. Then, on the other hand if Penn said he DID use before, they would argue "ah, he's just a druggie that wants to make his shit easier to get".
Those types will never listen to reason. No way to win with them. DRUGS R BAD M'KAY?