The new focus on privacy protections by Apple and other tech companies has a lot to do with the Snowden revelations, which damaged the public image of many US companies that were implicated in projects like PRISM. Being seen as too close to the US intelligence apparatus became poisonous for their businesses, particularly outside the US. To some extent, the DoJ's claim about this being a marketing strategy is not wrong. However, regardless of their motives, it also happens to be the right thing to do IMO, and in Apple's case it seems that Cook is genuinely concerned about this issue.
I believe that the secret services and "homeland insecurity" and FBI and whatever other US-non-democratic organizations put already tons of pressure and blackmailing on Tim Cook´s shoulders since years because he refused to join in their march towards Orwell´s Totalitarism.
When Tim Cook outed himself a year ago, I thought immediately that he wanted to prevent these organization from blackmailing him with this. At that time it was already obvious that apple stood under pressure.
I am also convinced that gay people of his age still know very well from personal experiences many years ago how detrimental it can be if privacy is lost and every single very personal information can be abused against citizens for whatever reason……
For those who claim "I have nothing to hide and I had never problems":
Pater Niemöller, a catholic priest had been put to death by the Nazi in a concentration camp.
Some months before his death and already prisoner in the concentration camp, he wrote some very touching, self-criticizing and wise lines:
"When the Nazis came to arrest the Jews, I did nothing, because I was no Jew…
When the Nazis came to arrest the Communists , I did nothing, because I was no Communist…
When the Nazis came to arrest the Socialists, I did nothing, because I was no Socialist…
When the Nazis came to arrest me, there wasn´t any person left to help me…. "
So: Stand up at the beginning and defend human right and your constitution - if you don´t there might be sooner or later not too much people left being able to defend these rights… G.W. Bush destroyed already too much…
Many Germans hesitated also too long to resist - they were no Nazis, but they hesitated - and one day there wash´t left any chance for voting or acting…