Hobby and Boop - I am not blaming her for her abuse.
If a friend of mine with a child said they were moving the new partner in that quickly, the kid was calling him Daddy, the finances were going to be joint, he was just out of another relationship, and the kid was going to need to get used to it that quickly, I'd think my friend was making a bad plan.
If it turned out the bloke was fine but the kid was taking a while to adjust, I'd think that was probably to be expected, because it was a bad plan.
If it turned out the new man was abusive, I would not be thinking 'ah well, you made a bad plan' - I'd think, shit, how awful for my friend.
The fact that moving so fast when you have a young child is not a good idea is not because the man might turn out to be an abuser - it's because young children shouldn't be subjected to such radical and rapid changes to their housing and their families just because a parent is madly in love.
If that reads as though I'm blaming women for being abused, then I don't think you're reading fairly.