Fair enough. I’m not saying “don’t use dark mode”, I’m saying don’t rely solely on it. Dark mode with brightness cranked up to 100% might be worse than light mode at 20% brightness if that’s appropriate for the ambient light you’re in.
I agree about contrast; to me white text on black background is about equally as bad as black text on white background (but fortunately most dark themes are not white on black). I look at text all day long and usually prefer something with a medium gray-ish background and light letters; in very rare cases I’d resort to a light theme just for its contrast (e.g. working on a laptop outside during the day and I can’t bring the brightness any higher).