There is no fake outrage - Trump simply said that if Cruz-supporting PACs are going to smear his wife then Heidi is fair game too. He warned of it to give a chance for Cruz to call off the dogs which Cruz can clearly do. Trump doesn’t have PACs providing cover for him so if they go after his wife he will fight back.
It’s not hard to understand.
Trump should be careful about that, as the attack on Melania came from an independent PAC and did NOT come from Cruz or his campaign. The Trumpettes and their candidate seem unable to make that distinction.