Braking the rules is ok, braking the laws is not. So if I understand, you would consider the people, that are in the drug business, as entrepreneurs? Illegal activities are highly profitable, precisely because most people, will not participate in them, and this distorts the market.
Of course they're entrepreneurs; operating outside the law certainly, but entrepreneurs none the less.
And in this particular case, why isn't it ok? He is clearly providing a service that the people are demanding.
It's more like the subway version of spam.
Clearly lots of people are demanding spam, right?
He's providing a service that a few people* are demanding, and most people find annoying.
Plus evading sales tax, creating litter, reducing rent from the legit concessionnaire, etc. If that's OK, why stop there, why shouldn't I set up a candy stand in the movie theater?
*the ones who take up one seat for each butt-cheek