Sounds like they're sorting through the contents: "We'll give away or properly dispose of your items."

Disposing items properly costs money. Donating items doesn't. So the incentive for them is to "donate" as much trash as possible. Then non-profit org will have to deal with it.

Sorry, I just don't like non-profits being treated as a free dumping site.

I hear your concern and I hope they have no intention of treating non-profits as a free dumping site. I would like to give them the benefit of the doubt and not just assume the worst of them.

More likely they will sort out the good stuff and give the rest to the non-profits.