I had that thought about Jin, too, which would also excuse Sawyer (also a parent.) But I think Jacob was blowing smoke up Kate's dress, honestly.

About Jacob, if his job is to protect the light from the bad people from across the sea, then his bringing so many people to the island and exposing it to so many potential baddies is kind of irresponsible. He's telling people that they've been chosen to do something very important which will save mankind, which sounds all noble and good and white and light but has very little detail.

Who doesn't want to hear that they've been chosen to do something special? Ben desperately wanted to hear it. Jacob even said in last night's ep that he chose those Losties because they had nothing, otherwise. Rather perfect pickings to choose a bunch of sad, otherwise not-so-special-to-anyone-else folks and give them something to feel special about.

I still think there's something to the idea that MiB is really protecting the light by killing off the baddies who would come to steal it. His methods are just a little gruesome, but I have to wonder who has the higher body count, Jacob or MiB?