I think his point is while Subaru does mean Pleiades in Japanese (actually came from Chinese), it (the name) has nothing to do with "seven sisters".
I don’t see anyone claiming that Subaru means seven sisters. It’s just another name for the same constellation.
[1]: https://web.archive.org/web/20100411083646/http://www.subaru...
Unfortunately, trying to find anything more online, such as what exactly the Kojiki says about them, doesn't seem to yield much.
So it is very similar to the lost Pleiad, but the seventh fairy is taken back by her god father.