It's a thing from 1000 years in the future man, you wouldn't understand .
As far as I'm aware, they didn't, her journal entry only says she went into hiding because she's too active and could be at risk.
Can't even say that this is a point she died before and she left a golem to die in her place, life 4 seems to be pretty close to usual 616 and she lived until after AvX.
The way it's worded sounds like simple paranoia though, which I guess is fair enough.
Also I noticed a small plot hole, on the journal entry I posted, Moira mentions the golem has her memories that were backed up by Cerebro, while in X-Deaths of Wolverine#4, Xavier says her memories weren't backed up at all:
I'm not sure why that was mentioned, it adds nothing because what Moira cares is getting her X-Gene back, and Immortal X-Men makes that somewhat redundant because Sinister has many clones of her.
Then again, having Moira's memories stored there could be a huge advantage for Krakoa, and this throwaway line can make sure no one can use her memories, well, besides Sinister, but so far he only cares to use her clones as a save state.