You obviously didn't read the initiative, by your own statements. It allowed for 5' x 5' square gardens, that isn't decriminilization? It allowed you to smoke marijuana recreationally, that isn't decriminilization? How were they going to tax your personal garden? Do you think it is fair that co-op growers/dealers can sell "surplus" tax free?
19 would have made growing and smoking LEGAL for recreational users. That was the point of the initiative.