Another portion of the article touches on the overhead to sort and store all these items for later distribution, that sorting might be done by volunteers (and thus be free-ish) but there's always an opportunity cost, the labour used for receiving these items is labour lost on other important projects.
If the charity is a responsible one then you're wasting more money by forcing them to sort your cans, clothing and miscellaneous junk than the slim chance that someone's going to misuse those funds
