There is one reality that's undeniable: that political donations by individuals are strictly monitored and can land you in jail if violated, but PAC money is untraceable and unlimited. That fact alone has led to stacking the deck in favor of lobbyists and monied interests at the expense of the electorate and national institutions.
I assume you mean Citizens United v FEC. Should they not have been allowed to release their documentary? Its not an easy question and there's a reason none of the dissents directly address Roberts' opinion.