Is my friend wrong to say HetaOni is too serious to have Fanfictions?

I think that serious sad ones are okay, maybe with a bit of comical relief, but like full blown funny ones aren't okay

HetaOni should be able to have fanfictions. Everyone has the right to write what they want.
But it probably won't be very maarufu if they don't take the story serious.
It's logical that many mashabiki will get angry then.
But if the stories is written good, and makes everyone cry like little children. Then everyone will upendo it without any doubt.