Yea it is strictly true, it's quiter obviously, but to say you don't hear it before it gets to you is a myth*, I live in a busy Low flying Training area, hear the fast jets all the time, you get little warning and trying to locate the direction they are coming from is very difficult, but to say you can't hear them till they get to you is just another myth repeated endlessly till people believe it.
*Unless as said before they are are over Mach 1 (770mph-ish at sea level) which is practicaly never in training and very rare even in combat
P.S. Years ago you either knew stuff like this from real life experience or you read it in a book.
Books tended to be peer reviewed and largely factual.
Today kids look things up on Google and get results that include lots of hits on forums like this where someone repeats a falsehood and they go off and repeat it themselves..etc etc
Combine that with the lack of critical thinking being taught in schools over the past few decades and the end result is millions of people believing all sorts of B---sh@t and insisting it's true