This is an enumeration of several Federer defeats that had a positive one - did not hurt his balance in the GS finals or did not worsen H2H with Nadal. You can add other losses. It can not, in principle, include losses GS finals or losses with Nadal.
US Open 2010 - If he defeated the Djokovic, he would not have won Nadal, who played the best USO edition in career. The best versions of Federer could overcome this Nadal, but the 2010 version is by no means the case. Djokovic thus protected Federer.
US Open 2011 - If he defeated Djokovic, he would lose to Nadal and worsen the balance in the GS finals and H2H with Nadal. Federer had a complex from Nadal, far stronger than when they clashed with AO 2017. There is nothing to suggest that Federer Nadal defeated USO 2011. So it's good for him to lose to Djokovic.
Australian Open 2013 - If he defeated Murray, he would lose in the final with Djokovic, whom the slow Plexicushion was it suits. Thanks to the semi-final loss, he has a better balance of winnings in the GS finals.
Australian Open 2016 - If he defeated Djokovic, the final with Murray would have to give up without fighting because he injured a meniscus after a semifinal. He would lose 11th GS final and 3rd in a row against Murray, who lost most of the AO final in history.