I do agree there is a major hypocrisy and double standard at play here.
Personally, I'm a separate art from art extremist. Will Smith deserved that Oscar and is a fine actor. Roman Polanski is an excellent director and Chinatown is one of my favourite films of all time. Harvey Weinstein produced some superb films. Entirely separate from all that are their crimes.
Will Smith would only have got into trouble had Chris Rock prosecuted. If a ten year ban is the result of his action, then I suggest Roman Polanski ought to have been persona non grata for some decades following what happened in the 1970s, and Harvey Weinstein ought to have a lifetime ban.
Regarding Polanksi, the Academy is particularly hypocritical, considering it granted him a Best Director Oscar in 2002 for The Pianist, long after the statutory rape incident. Yet after #metoo, they suddenly take the decision to expel him.