You are not wrong, but that isn't nearly as cut and dry as this. Language is socially constructed, that is true, but that is not necessarily what I think really makes this misconception this particularly egregious, but rather what makes it particularly egregious is multi-faceted.
Firstly, there was this video on YouTube titled "How NOT to make an indie game" which goes over an indie dev's journey into programming his own Roguelike in Unity. There is a point in the video where the developer says "My game is a mess, I have to start over" which is fair seeing that the game really had no direction, and I do not think the developer himself knew what he was doing. So, his solution was to get inspiration from other games on Steam, specifically "Roguelikes" and because of that, instead of a Roguelike, the developer made what I would best describe as a top-down arena-shooter. In the original beta tech demo for his game, his game might have been messy, but it was much closer to be a Roguelike with the grid-based movement and effect tiles (trap tiles) and the fact that we lost an authentic Roguelike experience for yet another clone of The Binding Of Isaac made me very mad that day.
In a nutshell, the developer was developing a Roguelike, but because it did not pan out the way he intended to, he got inspired by games he found on Steam to make another quote-on-quote "Roguelike", wrongfully thinking he was still developing a Roguelike and that misconception came from a spread-out misinformation that still gets perpetuated to this day.
Secondly, this asinine problem makes it harder for me (and other people like me) to find games that I like, thankfully the Dungeon-Crawler tag still works and that is the only way I can still find Roguelikes on gaming sites such as Steam, Itch and Gamejolt. Otherwise, I come across clones of Slay The Spire and clones of The Binding Of Isaac, the latter of which I have never been into anyway because, other than The Legend Of Zelda, action RPGs are really not my favorite genre.
Nevertheless, while language is subjective, it needs to serve its purpose. I can not imagine how a conversation between a fan of Rogue and a fan of Isaac would go like when the term that even link these 2 games together have different definitions, the other of which is wrong and so general that half of games ever released could be interpreted as "Roguelike" just by having the 2 features from Rogue. To add onto that, I am positive that some arcade games had a permadeath mechanic, and in addition to that possibly randomly generated levels too, this is beyond silly.