Why does it upset you so much? It is, as you say, a meme. Just a meme. It's not peer reviewed or held to any measurable standard that warrants getting yourself worked up over. It's not taught in schools or repeated on any serious news platform as fact. It's just a meme.
I too doubt if it is real. It's just entertainment. Just like when I watch a tv show, I can choose to momentarily suspend belief when I engage with it.
Is it flat out impossible for some native peoples to have had that quoted experience? I don't think so. I don't also think it would have been common at all. But not impossible.
Are you sure that it is not the sentiment of the meme that you are really objecting to rather than it's credibilty. Why not write a critical analysis of it. It would make for a more interesting conversation.
For one (speaking from my experience reading about the 'wild Irish'), there is often a might makes right in the anarchy of these losely connected groups of people that is often brutal. Those at the bottom of the social ladder probably wouldn't have such a rose tinted overview of it.
Interesting stuff. I think remember hearing about that in the Behindthebastards episode on Columbus.
The spanish had a similar native experience during an unplanned visit to Ireland in 1517. While there were towns and villages in Ireland at the time, there was still a significant population of wild Irish.
They spend an marked amount of time talking about the free range boobs that were on show.