Thanks!
Your concern is not that Eochaid is legendary then, but that the Geni tree should contain the mythological and legendary profiles?
There are arguments for that, but the discussion has been a constant one on Geni, and finally came down to the decision to cut the legendary and mythological profiles off, where it can be done, and also to cut the speculative connections, when we find them.
Leaving links to the previously connected profiles in the profiles still in the tree, and adding both curator's notes and links to the discussion.
the discussion concerning Niall is here:
https://www.geni.com/discussions/181054
but the overarching project is here: https://www.geni.com/projects/Testing-for-Fake-Medieval-and-Ancient...
and there are several discussions that are linked to it.
I can say that the view that the legendary and mythological profiles are legitimately part of the historical record -- being part of the history of how our ancestors have thought about genealogy -- has been voiced. (By me, for one.)
But the need for Geni to have genealogical validity is of much more concern to many.
and so this was a decision that was come to over long discussions, at many levels.