The article linked in the article gives some more information
Since then, this has been the technique of choice for moving rhinos out of tricky terrain but only for short stretches until they can be loaded onto a truck. They are usually airborne for 10 minutes or less.
The advantage of this airlift technique is that fewer people are needed on the ground because the rhino does not have to be rolled onto a net. This saves time and is kinder to the rhino which is unconscious for a much shorter period.
No ill effects
This is now the method of choice because it is quick and harmless to the rhinos always the main concern in these operations, says Dr Flamand, a wildlife vet who has overseen the translocation of thousands of rhinos during his career.
https://www.euronews.com/green/2021/02/02/hanging-rhinos-upside-down-is-vital-for-their-conservation]
I think its more like to save the rhinos they have to move them by helicopter to truck. They didnt set up the danger. The choices are tranquilize and roll them in net or tranquilize and transport by feet. By feet takes less people but the rhino is kept tranquilized less time.
Now the study says it actually is better.
I cant fault them for saving the rhinos by the what they thought was the best technique before they could probe that. The real crime is they needed to be transported.
Anyway your post pushed me to read the imbedded article so thanks. I didnt know they removed their horns after to protect the rhinos from poaching. They say painless and they grow back.