on how authors and readers are being pressured to not read or write anything that may offend others.
I'd say the complete opposite is happening as in there's more a trend for pushing the boundaries in the other direction. "The Human Centipede" springs to mind.
Back in the day, "Lady Chatterley's Lover" was banned. But it's very, very tame by modern standards. People have been pushing the boundaries of what's offensive to the point that someone's now actually came up with the human centipede concept. (If anyone doesn't know what it is, be aware before googling that it's... that bad there isn't even an adjective for it. Not one that I feel does it justice, anyway.)
The only thing where it's moved in the other direction (from what I can see) is when it comes to bigoted things like racism and homophobia. Society in general is a lot more aware of the harm done by bigotry, and that's a very good thing!
If someone's being deliberately hurtful and offensive to marginalised groups and will take the hit in the book sales and ride the storm of criticism, that's up to them (but they'll come across as a total bigot and if they start whining about "PC crap" in response to being criticised... that's just... *rolls eyes*) but if someone's doing that by accident - as often seems to be the case - well they probably ought to be advised regarding how what they've written will be taken.
Personally, I'd much rather someone called me out if I was accidentally offending people. I want to live in a society where things like being marginalised or discriminated against because of things like ethnicity, gender, disability and sexuality doesn't happen, so of course I don't want my words or actions making things worse.
And if I'm going to offend someone, I want it to be when I'm doing it on purpose or at least knowingly.
There are things in my books that I know will offend some people, and I don't care. The difference for me is who is being offended and why it's offensive. I don't want to add to the various racist, homophobic, sexist, ableist etc crap that people have to deal with on a daily basis. However, if I offend someone because what I write goes against something they choose to believe (like if someone who's homophobic doesn't like it that my young male MC has a love affair with another young man) then that's tough shit. They can learn to live with it or choose not to read it. They can even try to get my book banned if they like. It's not going to make me stop writing it. And I've never had anyone advise me otherwise - which is why I find it hard to believe that any "write what you want/PC PC PC PC PC PC blah" statement is anything other than "I don't like it when people call me out for writing something that's bigoted". (Acknowledging that it may be accidental bigotry not deliberate.)
Also, let's say (for example) I asked for advice about how to write a character from a marginalised group in a way that's supportive and not offensive, I'd find it rude if someone responds with something like "don't let the PC brigade (or whatever nasty epithet gets used nowadays) curtail your freedom to write what you want." Yeah, cause I'm already writing what I want...? I thought good writing was about getting the intended ideas across and not accidentally saying something completely different that you didn't mean. Like if you meant to say "New York is a great city" but you accidentally say "I am a fish" then that's crap writing. If you ask someone whether "I am a fish" adequately conveys the greatness of New York, the correct answer is "no", not "don't let the PC brigade curtail your freedom to write what you want".