I'm for decriminalization because if you can't admit you have a problem and need help without being charged with a crime, it's a barrier to getting clean. I'm also generally for "It's your body. Put what you want in it."
I am not criticizing this change in policy. I am also for holding people accountable for their behavior and not excusing bad behavior generally based on "Poor baby. Has an addiction."
We don't say chemo patients are excused from behaving appropriately, though we do make allowances for the fact they are probably grumpy and not at their most diplomatic because they are miserable. I believe addiction frequently has an unrecognized medical component and people are literally self medicating, often for an issue that doctors have failed to identify. I believe if you find the underlying cause, they can stop.
Anyway, just trying to give context here. Decriminalization should not be code for "Let's let assholes claim the rules don't apply to them at all and excuse all their awful behavior."