Framing
It's the phrase "be able to." It sets people off. It implies an absolute moral authority something enforceable. It's a threat to deny people their ability to write, something that writers probably value a little bit. But the thing is that of course you're able to, always have been. always will be.
There's a long history of white male writers being able to write about whatever race or nationality they wanted, to use, fetishize, change, those races and nationalities to express the truths they wanted to. They got to write what they didn't know by making it up, making a nice imagined group of people that blocked out the real group, which had already been cast out of any position to tell their own story. Then they got to pass on that imagined people to the next generation of writers, writers who followed in their footsteps, still white, still male, and now making things up about made up things about ignored people.
Things change though, slowly. The ignored fight to tell their stories, fight to be heard over the made up voices. Our society's writing is a part of that process, and we have a moral obligation to consider that. I do not want to in any way offer any concrete answers or rules. In general I have no clue what the fuck I'm talking about, and am a white cis male asshole who has no personal expierience of this. I do think that it is our individual duty to question ourselves and our writing in this regard though. Our words don't exist in a vacuum and we have to be concious of how they interact with our cultural histories of oppressing and silencing others.
However I think that these are all questions that should be dealt with when we edit and reread our writing. I think it's an excesive burden on creativity to be constantly second guessing ourselves as we're in the proccess of creation. What we write is a reflection of who we are and our thoughts, and as long as that is given critical thought and reflection there is absolutelly nothing wrong with it no matter what it is. It is when we share and give out those thoughts into our wider culture that we become acountable for our works impact.
I know that I have written shit about charecter's of other races and nationalities that showed a lot of my blindnesses, biases and flaws, and while I have no intention of ever letting any of that see the light of day, I don't particularly regret having written it, despite the fact that I hate myslef for being a person who would write it. Those pieces are hopefully a part of a proccess of being less like that which I will continue to work through.
So yeah of course people are "able to" write charecters of other races and nationalities, but I would hope that those writers are considerate and concious of the history that their writing is a part of and the impact it might have.
Also just a brief mention, I wrote a longer post about similar topics last year which is linked to here if you're interested: