Earlier quoted context omitted.
Is that a flaw in media queries, or we devs writing bad queries?
Flaw in media query. They work on resolution and on pixel density as reported by the device but you have no way to know if it's a small size high density screen or a large screen with average density. There are 13" laptops with a resolution which overlaps with the higher end mobile phones and that is where mq falls apart because you can't tell where you are. The real issue is with all browser reporting the same fixed…
I'm certainly unaware of browsers doing this, except for a few old ones on desktop and Windows Phone 8's IE, and I can't find anything claiming other browsers do this. Certainly it's never been an issue I've hit.