According to Reddit…so, grain of salt…that is an urban legend, related to a Neil Gaiman short story that appeared on the Matrix promo website.

https://www.reddit.com/r/movies/comments/1amree7/theres_a_wi...

I think we the urban legend really sticks around because the compute explanation just makes much more sense and we all want this beloved movies not to have a sill (albeit inconsequential) plot hole.

Oh, totally, it’s my head canon as well.

Mine is either that, or, the idea I mentioned in this post:

https://news.ycombinator.com/item?id=47185076

Machines trying to be benevolent, but overly controlling.

That's very good.