"topics" is also how untested, new fangled things like book stores and libraries work. People are also far more likely to side scroll menus on mobile. I'm not saying it's great design, but the option is there. ITunes store, that example of perfect design /s, uses side scrolling a lot too but it only really (half) works and only with the apple mouse.

I really hate hamburger menus on desktop because as you say, it only says "this is a menu". On mobile: navigation, on desktop (FF & Chrome) it means options. And then on Chrome they have tried to shoe-horn everything into a stupidly small pop-up where half the options are just links to open more options. It's hardly a step up from a menu bar.