I’m sorry but you are pulling out some horrible accusations with 0% evidence.
The simplest answer is usually the correct one.
Primo entered the draft too early and is mentally struggling as a result. This seems to be the same situation as Tyrell Terry and Dallas. The reason they cut Terry was because he needed a stable environment and there are only 15 spots on a roster.
They just guaranteed him more than $4 million for next season, now three weeks later they're cutting him without attempting to trade him? They're not sending him for a stint in the G-League, or putting him into an NBA counseling program, but instead are cutting ties with him completely?
Oh, and they also stopped selling his jersey in the team store, and erased all evidence of him off of Spurs instagram, purportedly.
Something big happened here. This situation is unique in recent NBA history.