The tents & more often tarps are providedby a small number of pastors and volunteers who have what they think is a very Christ-centered approach to homelessness. They wantt he homelss to be visible and they welcome out-of-area homeless to PDX .
A church known as Home Forward and another churck called Anawim are two of the groups who say that we must house everyone and the homeless are not accountable as long as Portland area residents do not take them into their homes or otherwise provide food and shelter (I read their FB pages- they say crap like this).
So, if you don't take your marching orders from a bronze age text said to be supernatural in origin, well too bad because the pastors get the last word.
Dr. Know- you got the source of tents wrong.   People are giving nice tents to junkies.  Check out Home Forward and the loonies at the Red Barn.