First of all, I basically agree with this. Here’s something I don’t know: Sometimes I wonder whether some people in prison for non-violent drug offenses did a plea bargain down from a violent offense. And if that were the case, should this affect our opinion on any of this?
I'll throw in another part where more fine-grained control would be nice: the amount of said substances is measured by gross weight, baggie included, even if whatever the substance is has been "stepped on."
Now, wave a gun in someone's face to take their money for drugs? Keep that charge. But otherwise we should not only free, but expunge the record, retroactively. Some kid with a dime bag ends up having to suffer for that decision for the rest of their life.