A) There is no artistry in just making offensive material. You aren't making art, you just wasting people's time. (This might be because I've been reading Captain Underpants which is meant to be offensive, in a kid way, but is absolute trash because it's just trying to be offend and nothing else. They are a bore and a chore to read.)
If a person makes a piece of art that happens to offend people, that's different.
Now, to your point. Most art is pleasing and less demographically targeted by design. Mona Lisa, Girl with the Pearl Earring, American Gothic, Mario... Most of Nintendo's catalogue for that matter, Lion King, Harry Potter,...
I can't imagine anyone calling Dune an offense. And it's smashing it at the box office right now.
Most art goes out of its way not to be offensive and is not aimed at a demographic.
B) Publishers have always had the power to cancel people. They have been doing it for centuries. They didn't need to be people to do that. It's inherent in their nature, by design.
You can, of course, want to take away that power. But you don't actually want to take away that power. You just want them to go back to when they only used that power on lefties. When you grow up, I can join you. But you have to realise that this means that you have to make all publications done by the government. You cant force a company to invest in everything. That's not how capitalism works.
C) I mean, Musk, Bezos, Koch, The Zuck, Dorsey and Shapiro have all said very similar things about forcing their ideas onto others and cancelling people. But then, that's not really what this is about