I'd hardly consider this "trying to be PC".
https://i.imgur.com/cgGx4JR.png
This is more about bowing down to America's backwards views on sex and nudity, most likely in order to appease advertisers and/or Apple.
Apple has nothing to do with this. Tumblr was removed from the app store specifically because of child porn; plus, if the anonymous sources are to be believed, Tumblr have been working on this for >6 months, predating the app store snafu.
I don't understand this statement. Tumblr's user base, at least the portion who disagree with the site operators on this, are usually the ones accused of being “politically correct”?
It's as dumb a move as you can possibly make; I don't know what the decisionmakers behind were smoking, but it must have been something strong.
However lately, those on one side of the political spectrum in America have co-opted it to paint the other side as overly sensitive/weak etc. muddying it's original intent, often using "concern trolling" to rile up debate.
Examples: Sexual harassment, blackface