The article has this:

"UPS says while it may sometimes reach out to the recipient for information, generally the original shipper is responsible to provide what’s necessary. In the case of incomplete info, the UPS statement indicates the package is considered abandoned and “we dispose of it in compliance with U.S. customs regulations.”

UPS can also return the package to the shipper if they pay for the expense."

With the emphasis on "in compliance with U.S. customs regulations."

UPS is not the "owner" of the package, so would be prohibited from selling it, and profitting in that manner. "In possession of" is not ownership.

Customs itself, on the orher hand, when they sieze illegal goods, become the owners, and have stated on a video I watched that they occassiobally give items to charity. These being counterfeited goods like sports logo shirts and the like, and with the permission of the companies whose logos were counterfeited.