It’s primarily motivated by control; similar to how all narcissistic, abusive, controlling, murderous, “dominating” (as the document itself proclaims) people and systems are. That is not motivated by magnanimity and genuine shared interest or focus on precision and accuracy.

The controllers of the whole system want open weights and source to make sure models aren’t going to expose the population to unapproved ideas and allow the spread of unapproved thoughts or allow making unapproved connections or ask unapproved questions without them being suitably countered to keep everyone in line with the system.