Does she gives any reason for this? By thought would be that's just her recipe, probably a taste preference. I once found dates they had a very crunchy texture and were small in comparisons to medjool, no idea what type they were but they were by far the best I ever tasted, too bad they stopped selling it at my grocery store.
Just because Freelee or Durianrider do something doesn't mean you have to. The key point is living a high carb vegan lifestyle, not copying everything they do.
I would argue that barhi or khadrawy dates are better for daterade anyway.
The deglet noor dates (or smaller ones) do not blend up so nice and creamy as the big juicy medjool dates prolly thats why.. ^^