You really want us to believe there are people in prison for these offenses? 
Sorry, there is some confusion here. I didn't read what the ACLU was advocating because no information was provided. The public often uses jail/prison interchangeably. The title of the thread says "jail" not prison. But I can understand your confusion. Having recently been reading about a similar push in Ft. Worth Tx, Austin Tx, and some other jurisdictions throughout the country to reduce arrests for minor offenses that was where my mind was at in my response. I apologize for any confusion.
"Why We Need to Change Policing Now
As health and medical experts have said, all local law enforcement should be taking whatever steps they can to reduce the number of people that they arrest and put into jail during this public health crisis. Senior staff attorney Carl Takei explains why."
The above is a headline I just took from the ACLU website. It appears I was probably on point.