Do professional writers have to consider this "new reader" from a commercial point-of-view or is Stross just thinking about how he might adapt his writing to this group to be gracious towards them?

Not sure if there is some way to iterate given online feedback. Like, write a book from the pale, male, and stale point of view. Use an LLM to gather feedback on what people criticize. Then write almost the same book again, from the POV of a different character, taking into account interesting criticisms.

However, it may be better for a successful author to just get away from these hyper-online criticism spaces and write what they want to write, as long as they've got books lined up they're already excited to write.