I don't mind stoned people personally, they tend to be quiet at the very least. I'm just discouraged that many are unaware of the health risks, particularly related to heavy usage. In a sense the hyperbolic language of the anti-drug people has pushed an opposing equally dismissive logic on the part of the recreational drug users.
I know people who would never smoke cigarettes due the expense and health effects who glibly use marijuana without a care.
It's yet another good reason to legalize it. You can ensure people know what they're getting into, and deal with the negative consequences to its usage in a systemically rational manner as we've been trying to do with alcohol-abuse and smoking for quite a while now.