Why not? I'm pretty sure they know roundabout what it would cost to tear it down, so why not see if someone is willing to buy it because they think they can get the work done cheaper and make a profit off the raw material.
There's an idiom in US english, "and if you believe that, I have a bridge to sell you", meant to imply that someone is gullible. It's usually what's being referred to when someone is talking about selling a bridge, and is a source of humour when someone actually sells a bridge.