up until a few days ago, i would have rejected the premise of the question. alas...

the reason is just simply that the nazis didn't have time to wipe the slavs out in numbers comparable to the jews. it's less that the nazis saw the jews and poles differently (although they did see them differently, it didn't make a difference in their prescription: there was a final solution for poles, they wanted both of them exterminated.) and more that there were just way, way more slavs to exterminate over a much larger space, so it required a longer term strategy to do so.

again: the estimates are that upwards of 25% of the population was killed. it's not 90%. but it's a start.

i apologize for the grim statements, but this is the actual historical truth: they got a quarter of the way into it and ultimately lost. in the end, they got outnumbered, even - and that is actually the truth of it, in the end, the russians just simply had more soldiers, and were consequently left standing after the slaughter.

it's not due to a difference in intent. it's not due to a difference in design. it's just a question of how far they got into their plans before they were ultimately stopped, by one of their prime targets for extermination.

if the nazis could manage to wipe out a quarter of the slavic population in what amounted to about three years, it stands to reason that if the war had gone on another 6 years or so, we'd be up to around 75% of the population. and, with the absolute destruction of the jews, the nazis would have focused squarely on the slavs, so it would have picked up in pace, as well. it could very well have reached close to 90%.

do not doubt the intentions. and do not forget the dead. call it an accident of history. but, understand what happened, please.

https://www.reddit.com/r/AskHistorians/comments/3efw1g/why_arent_slavs_normally_counted_as_victims_of/

jagmeet singh must cut his beard