Reefer madness

I don't understand this.  I don't understand why 55% of polled Americans still oppose the legalization of marijuana (though they favor it for medical use).  The article provides precious little explanation for why people oppose legalization, only a couple of explanations from two or three individuals. 

I personally don't have a big dog in this fight; legalization is not an issue I care much about.  But I do think it's pretty silly we have criminalized pot and I think it's a giant waste to spend precious government resources to prosecute marijuana laws.  I have personally seen guys sent to prison for possessing a few seeds.  That case took one county attorney, one public defender, one judge, and a slew of court personnel for 4 months leading up to a trial.  Then it took one county attorney, one public defender, three judges, and a slew of court personnel for the roughly 18 month appellate process.  This is a gigantic waste of public resources.  And that's just one case.  In a state that's drowning in debt, it's just flat irresponsible to keep focusing on piddly little nonsense like marijuana.  But according to this article, about half of the respondents thought that the cost of enforcing our current laws is about right. 

I can't really just agree to disagree on that one.  We spend way too much money criminalizing a drug that's just not that dangerous.  It's certainly no more dangerous than alcohol.  It's less addictive than tobacco.  So, if you oppose legalization of marijuana, I'd like to hear why.  What am I not seeing that justifies our continued expenditure associated with the criminalization of pot?