I assume this was the fastest way of creating and mass producing AI for combat, an electronic copy of the human mind. Even with the Traveler, the mind is still one of the most complex and powerful entities in existence. Honestly it would make a lot of sense to try and more effectively weaponize it.

Have you heard the legend of the Deep Stone Crypt?

Enlighten me.

The Deep Stone Crypt, is the infamous subroutine which seeded the first Exo consciousness. [spoiler] [quote][u][b]Deep Stone Crypt[/b][/u] This is the tower where we were born. Not the Tower. Just a tower in a dream. The tower stands on a black plain. Behind the tower is a notch in the mountains where the sun sets. The teeth of the mountain cut the sun into fractal shapes and the light that comes down at evening paints synapse shapes on the ground. Usually it's evening when we come. The ground is fertile. This is good land. We go to the tower in dreams but that doesn't mean it's not real. Some of us go to the tower in peace. They walk through a field of golden millet and a low warm wind blows in from their back. I don't know why this is, because: The rest of us meet an army. You can ask others about Deep Stone and they'll tell you about the army. They might confess one truth, which is this: we have to kill the army to get to the tower. Usually this starts bare-handed, and somewhere along the way you take a weapon. Ask again and if they're buzzed they might also admit that most of us don't make it to the Tower, except once or twice. None of them will tell you that the army is made of everyone we meet. The people we work with and the people we see in the street and the people we tell about our dreams. We kill them all. I think because we were made to kill and this is the part of us that thinks about nothing else. Often I kill people I don't know, but like most of us I think I knew them once, in the time before one reset or another, when my mind was younger and less terribly scarred. So that is how we go back to the Deep Stone Crypt, where we were born.[/quote][/spoiler]

Killing an army of everyone you know? Sounds scary as ****

I skimmed the entire thing from different sources, it still supports my claim. The human mind is powerful, so is it's will to survive. Whether exos are future humans or that their initial programming suddenly became self aware. Nothing changes the fact they exist, and whether they like it or not their mind parallels that of an organic being. It also makes Banshee's "reformatting" comment more valid, it is likely that in order to adapt to fight or defend themselves, they would have needed some form of firmware update that could have fragmented or corrupted bits of their memory. That being said it doesn't change my option that exos deserve love if they wish to seek it out.

There's a Titan mark that is supposed to bear the image of the Deep Stone tower. If you take a good look at it you might find that it bears striking resemblance to a Vex conduit. I suspect that as the lore develops we might discover more links between the Exo and Vex. I've got this sinking feeling that the Deep Stone subroutine might have been made from Warlocks in the Ishtar Collective messing with Vex data.