I disagree. Strongly.
The examples you've given of things that are important to say, are both ones of justice and fair treatment of historically marginalised people. I think you're arguing in a bit of a dishonest way by doing that. Not everything somebody would feel compelled to censor is something well-meaning, harmless and that we can generally consider "nice progressive values".
Do you believe that those who beliefs are homophobic, transphobic, racist, paedophiles and fascists are also committing an evil if they choose not to include such things in their work?
People who experience paedophilia basically can't help being attracted to underage people, and it's only through their own willpower and self-censorship that they can function in society. It's not evil of them to choose not to act on their urges.
Orson Scott Card is a fantastic sci-fi writer... and also a massive homophobe, like he really hates gay people, he thinks being gay is bad for society. It's never in his books, though, is that a bad thing?
Compare J K Rowling, who is a TERF, a transphobe, and recently wrote a book about an evil transwoman who uses being trans to infiltrate "women's spaces" and murder them, even though everyone told her that's a really damaging bit of transphobic rhetoric that would make life harder for a marginalised group who already face a lot of violence and oppression. She genuinely believes that trans women are actually just men disguising themselves as women in order to sneak into "women's only" places (like changing rooms, support groups etc.) make cis women feel at ease, or force them to accept them because it's "politically correct to do so" and then sexually abuse and hurt them. Do you believe it would have been an evil if she'd chosen not to reflect this belief in her work, knowing that she has spoken out saying this and contributed towards trans rights in the UK going backwards and trans people being more oppressed?
If somebody believes in gay conversion therapy, is it evil of them not to speak their truth?
What about if they believe autistic people have no real autonomy and are just burdens that will hurt others, like Sia did when she made the movie "Music" just a couple of years back, with guidance from the organisation "Autism Speaks" which espouses the same damaging rhetoric? Is it good that this non-autistic person felt the need to speak out on her ideas about autism in her art, even though they're damaging and unsupported by science?
Because this is the problem; freely being able to say what you like without censoring yourself isn't as simple as "it's always good to do it and it's evil not to." Some people believe things that could hurt others, or are just ignorant. Sometimes maybe it's actually good for a person to stop and think, "This isn't my story to tell." or "This is how I see the world... but maybe I need to encourage others to be a bit open minded and come to their own conclusions about it." People who aren't from a marginalised group are often struck with some bolt of inspiration and want to write a story based on tropes they've seen in media and end up misrepresenting a real group of people and perpetuating harmful stereotypes. Like not acting on an intrusive thought while driving and just going headlong off a bridge or into a tree, perhaps self-censorship is sometimes a wise thing?
