Yep, we need to tell newcomers more honestly how Linux works.This has happened twice to me in less than six months, so it is definitely a thing.
There are many "well-meaning, wishful lies", as I'd like to call them, out there on the web (not so much here). (And a few ill-intended ones too )
Suggesting things like "your PC will run much faster on Linux, it's more lightweight, takes up less disk space too!" or "don't worry all your Windows apps / games will work just fine, even faster!" or "it's super easy to customize Linux and backup / save all your settings / software, it just works!" or "just use separate home partition, everything will work after an upgrade!" Just not true.
Most of it comes from either ignorance or having high expectations. As the article explains https://linux.oneandoneis2.org/LNW.htm in order to justify the time / effort of switching from Windows, people expect Linux to be better than, but also the same as, Windows.