I wonder if they somehow got mixed up about a book that suggests clipping the leaves of the clones that will be rooted.

I do this and I think it does help with the plant's tolerance to being amputated and is now dependent upon itself for everything. Because there are no roots, the plant cannot support the majority of each larger leaf. By doing this, it seems to tolerate the trauma better and I think with some species, make them root faster.

So, possibly that is what the idea was way back and then during the telling it got lost somewhere.