No, its not pedantic. There are real people who will have real and negative health outcomes if drugs are legalized. Ignoring this in the conversation about legalization is to our (society's) detriment. The post which began this chain wasn't only ignoring this outcome, it was asserting that it is not a possibility.

Yes, there are more people who are more negatively affected by the current state of affairs. The law should change. But we should also be cognizant of the consequences of that change.