You caught MCU Thor in a lie. No one in the MCU is as knowledgeable about history as you are, so they haven’t caught on yet. Of course, the writers also probably don’t know, don’t GAF, and if they ever do notice and do anything about it, they’ll invent something random and probably equally arbitrary on the spot.
If there’s one thing consistent about the MCU, I’d say it’s that it is mostly
d u m b, apathetic, and inaccurate about almost everything, and their Norse mythology is almost all reinvented reshuffled nonsense.