Hard disagree. Accessibility matters, and some of us are photosensitive to large amounts of bright white. Design your CSS to not completely break with a forced dark theme and this won't be a problem.

It matters to you. Why are you projecting your needs onto others?

Perhaps there's a nicer way to say it? "If the author so pleases, he may consider improving accessibility by making it compatible with Dark Reader."

Then it is phrased as a request, rather than a complaint or critique.