DR - quite strange. I would have though Salvation Army or Goodwill would take them as long as they are in running condition.
Here's a contradicting link:
GE Appliance Donation Center
GE is saying to call 2 of the places you said won't take them to arrange pick up.
Perhaps the closer stores won't accept large appliances. I'd call the Frederick stores and see if they accept. I'm pretty sure I've seen the Goodwill take used appliances before.