Why apparel specifically? Because apparel is specifically the consumer industry where enormous quantities of unsold product are intentionally destroyed to then be replaced in the market by newly made equivalent articles.
Why was USB-C mandated specifically on Apple devices? Well here's the thing: it wasn't. It was mandated on smartphones in general, and Apple was the only company that specifically tried to fight the regulation because apparently they're special.
Because it is very visible to low information voters who are also red/green voters.
Is there such a thing as fast-cutlery? Or fast-furniture? Maybe fast-book or fast-vehicle? Fast-whitegood perhaps? I'm at a loss here, I've only heard of fast-fashion.
There is no law that states specifically Apple must specifically use USB-C. IIUC, the law is that all brands/manufacturers should use the same type of charger, an industry standard. That was apparently USB-C. Apple was the odd one out and had to change. If something better comes along, the industry as a whole can upgrade.