Is tinder a real word? I thought it was just a made up word for an app? I can't be expected to explain such words in another language when I can't explain them in my native language. But I think if you said spark instead that would be more reasonable such you need to rub two pieces of wood together and create a spark and then a fire starts.
Well the way I learned it, you kindle fires by igniting the kindling. The kindling then ignites tinder (an intermediate stage), which then ignites the real fuel.
But I also often hear the two-step usage where tinder is includes kindling.
To me it's just the opposite. It's why the concept of a tinderbox makes sense (it contains grass or paper or something else easily ignited by a spark or small fire).
Kindling is actually a verb, as in, the act of 'kindling' a fire, even though it's also used to describe the material used to kindle a fire. Tinder is just the material.
Perhaps you are complaining that gerunds (which are already nouns) can grow extra meanings over time. But all languages do this kind of stuff.
German has exactly the "problem" you are talking about, only worse. Depending on capitalisation, "Essen/essen" can be the noun "food" or the the verb "to eat", But when used as verb, it is usally used in the sense of the English gerund "eating".
