Not him, but true soul is when an artist gives it their all, and their passion shines through. Soul is not necessarily good or bad quality. It can be either good or bad, or somewhere in between. Rather, soul is the knowing that the artist did everything they could to make somethings as good as they could. Things like deadlines, skill, and tools are taken into account.
So a shoddy animation with a tight deadline can still have soul, since the limitation is accounted for. A movie with subpar effects can still have soul, accounting for the limited tools the studio could afford. A game with less than stellar graphics can have soul, accounting for the small size of the dev team trying to carry the entire production on their shoulders. Stuff like that. Notice, that all of these examples are incidental circumstances. NOT intentional.
Forced soul, is when you *intentionally* produce shoddy work or limit yourself, in order to try and replicate the soul others captured naturally.
Note: Limiting yourself is not the same as using simplistic art styles. You can make a Veggietale's art style today and still have soul. But you have the tools now to make a better. So limiting yourself unnecessarily by using older programs is trying to force soul.