Absolutely and I don't blame you. The ancient lineage stuff flew up my flags when I first started too. I had years of TKD kickboxing training before HRD and I had heard the stories your talking about as well. I still run into it, although not as much as I used to. When my friends introduced me to HRD and I heard the same stuff, my response was "Awe, you need to believe pseudo-history to justify your training. That's so cute...." (Yup, that was me in my early 20s). But the diversity of stuff we do in HRD is what drew me in, not to mention the community of the local club that I eventually became the Head Instructor of. My involvement with HRD forced my TKD friends, including my little brother, to actually look into the history (which left most of them quite jaded and some quit training because they felt they were lied to) and it forced me to dive into the history as well."
And to be fair, while most people recognize the early history stories as nonsense driven by the cultural need to distance Korea from occupying Japan after the liberation, there are still those who try to claim ancient roots for pretty much ANY MA developed in modern Korea.
Happily, the silly histories don't really have any impact one way or the other on the system taught.