The article encourages to reuse unused soap. But, before that, we need to compare energy consumption between disposing soap and recycling soap.
Soap in each hotel's room must be processed at factories.
It needs energy to transport unused soap and to process.
If total energy to recycle soap is less than that to dispose soap, we should obey what the article says.
The company cleaning up the world's biggest hotels
http://edition.cnn.com/2017/05/01/hotels/clean-the-world-asia-hotel-soaps-recycle/index.html