User blog comment:Kaido King of the Beasts/Chapter 866: The Iron Non-Giant/@comment-26858217-20170525144105

Well, gotta say the giants got the good instinct/impression about what Big Mom can and will be. It may  looks like an Ohara or ""Demon's spawn " some thing, but the looks on Big Mama definetly said that she isn't the type to just become good like that.

I think the old giant just acts on what thinks would be better for the world, or at least his village.