While it is disappointing, I can understand why thrift stores don't want to sell computer gear.
I recently walked into a Salvation Army. They had 3 computers (one of which was tempting), and approximately 20 CRT monitors (again, one of which was tempting). The former, unfortunately, are hard to sell. Even if I wasn't making a big move in the near future, I would have to put as much serious consideration into buying a $5 computer as a $5000 computer -- just because it is too easy to acquire too much. As for the monitors, those are just toxic waste.
Then there are other complications, ranging from staff who don't know what the stuff is to donors who don't know how to maintain their privacy.
It's too bad, but I totally understand their anti-computer dontation attitude.