Imagine if every country respected the endonyms instead of us imposing made up names
Names like "Germany" have been around for centuries and are no more made up than any name in any language is made up. The tricky part with "Germany" - or "Deutschland" - is knowing when to use it and just what it means at any given point in time and that's nothing to do with the language.
It doesn't seem sensible if, by using an endonym from a language that I know nothing of, I create confusion. For instance, should I be using "Bhārata" instead of "India"? That's hardly meaningful to my relatives. Or should it be "Hindustān"? Or another name from the other languages of the "Subcontinent"? And is one of those names liable to upset people from what is now Pakistan or BanglaDesh? I'd rather be neutral and use the English term.
If the world turns against exonyms, then I'm happy to follow the language, but it has to be that way round - the prescriptive approach doesn't work, which is why we still have split infinitives.