Who were the Season 5/6 Others?

Okay - doing a final rewatch since Netflix is dropping it, probably like a lot of other folks, so sorry for being one of 'em.

>!Originally, the "Others" were Black Rock survivors and...others...that Jacob had pulled to the island over the years, called "Hostiles" when Dharma showed up. Then by the time the main cast is on the Island, the Others are those same people + what was left of Dharma, being led by Linus after he was sent there by the main cast in the past. Then they all get time-wonky. But eventually, we all return to the present - \~3.5 years after their initial crash, give or take, though some (like Sun, Ben, and...the pilot guy) were already there. But when Jack, et al, show up, the Others act like they have no idea who they are.!<


I don't follow this. That's not a long period of time, and by then everyone knew the main cast because of the multiple encounters with them. So...why'd no one know who they were? Or did I miss another group arriving during that time frame?

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@lostbackup