That dark theme screenshot is bad and light theme is good is nuts because if theme is important you provide a 50/50 screenshot showing off the themes.

I don’t think that was the point, it says “Having some screenshots to show off that e.g. dark style is supported is fine.”

If you look at the screenshot, it shows the app using a weird font, as well as non-default header bar buttons. That’s the main area of contention. Screenshots showing weird fonts, non-standard window additions, custom themes, aren’t recommended.

Showing the app supports dark mode is completely fine.