Again you are applying morality in impossible situations. It is not a matter of you or me being right or doing the right thing.
I'm talking about how living beings act, live, learn and evolve, whether peacefully or not.
To be fair it is true that 10 lines in time do not correspond to all the temporal lines or alternate universes in marvel. However, from Xavier's point of view, even though he believes in some future where humanity and mutants
live together, the fact is that he doesn't know
how to get to that happy ending. The most he can do is see where he failed in Moira's visions and prepare for the worst in the hope of being enough. Imagine a game where you have 5 bad endings and a good one and only one chance to get it right. That's more or less what Xavier is dealing with.
If Xavier makes a mistake it is the end of the mutants and this time they could no longer count on Moira and another chance (technically there's a catch here about Moira's lives).
Yes, there is a timeline where she and Xavier tried the path of pacifism and failed horribly.
Interestingly, you believe that Moira is the reason mutants fail. She tried to eliminate the mutant species before being killed by Destiny and this change the point of view of her actions in other lives
. However, even without her interference, certain patterns were always repeated as the creation of artificial intelligences.