It is, of course, nonsense. BTC effectively defines the term cryptocurrency, there is nothing about BTC which isn't found elsewhere in other cryptocurrencies, many of which are chain or code forks of BTC anyway. It's the biggest name, it was the first mover, but the claims that it is a separate phenomenon all of its own are relatively recent (or have increased markedly in recent months) and are IMHO hilarious.
That's not something that you need to wait to know about. That's what the word means.
It doesn't matter if you think bitcoin is amazing, and will take over the world, and is basically the currency of the gods. It doesn't even matter if your pipedreams about it destroying fiat currency come 100% true. Bitcoin falls within the category "cryptocurrency", and the attempt by yourself and other BTC fans to paint it as a separate phenomena is fucking ridiculous to observe.
If you truly believe that the first cryptocurrency is not a cryptocurrency, you might want to examine what has happened to your cognitive faculties. I'm not even saying that to be mean, you've stretched something beyond breaking point with the mental gymnastics there.
You've even said it in the post you linked to!
> And the only way to do that is via 1 single cryptocurrency: the very first, the only one
From your own fingers!
Seriously, this is embarrassing.