I think the reason for this is that Will's actions are directly related to the Oscars. They want to save face. The dealings of those other people, while vile and long term, aren't directly related to the Oscars. No one is associating their behavior with the Oscars like they are Will's. That's just my guess at reasoning.
Dj Jazzy Jeff defends his friend Will Smith
https://www.blackenterprise.com/dj-jazzy-jeff-defends-his-friend-will-smith-it-was-a-lapse-of-judgement/?fbclid=IwAR3Gc06ewW8TbXb1wD6efit2Y6MTPCg99ZQHW7lzzYGre-ovwQI6StOaZSg