SRO stands for Single Room Occupancy. This used to be normal market housing but we have torn down about a million of them in the US since the end of World War II, thus it's a form of housing and a term that are both going extinct.
So people on the internet frequently either don't know the term at all or they associate it with transitional housing for homeless addicts in recovery trying to fix their lives and get back into "real" housing. People often think I am talking about "poverty housing" and homes for the homeless and that's not what I'm talking about.
I largely stopped trying to converse on the Internet about housing issues. It proved to be an exercise in frustration and miscommunication.
Instead, I began working to flesh out an explanation of what I'm talking about HERE. This site is my attempt to update the concept of small living spaces intended to hold one to three people that constitute affordable market-rate housing, NOT a welfare program and NOT poverty housing that lacks essential features necessary to establish and maintain a full life on a reasonable budget.
See also: What is an SRO?