I think I've come across an article similar to this in the past. However saying that bitcoin is the first crypto currency is also very correct but may seem a little vague for someone who really Keens into the contents of this article. Now personally I really never thought bitcoin was the first attempted crypto currency even before I read an article like this back then. And my reason was simply because in order to create something as secure, sophisticated and complex as bitcoin there must have been a couple of failed attempts in the past even if they weren't publicised.

The idea of calling bitcoin the first crypto currency is because it was the FIRST SUCCESSFUL crypto currency. Also generally the term altcoins was implemented to other coins so people literally call any coin that isn't Bitcoin and altcoin. Others like; meme coins,  and shit coins are like sub terms under bitcoin.