About a quarter of under-30 men and a fifth of under-30 women. For comparison, about 20% of Americans "think holding neo-Nazi views is" acceptable [1].
> excluding people who don't vote and have had their voting rights taken away
Where do you see the 2% of Americans [2] who have had their voting rights taken away being excluded by either poll? (Not challenging. That's just methodologically impressive.) Either way, none of what you're citing is material to an 80/20 margin.
I have friends in that 17%. But I also know people who thought Kari Lake was a shoe in, "defund the police" would work or that every guy is an incel. Echo chambers are powerful, especially online, where they can convince a quarter of a single demographic that they're in the majority on celebrating a dude capping a stranger in broad daylight.
[1] https://www.the-independent.com/news/world/americas/us-neo-n...
[2] https://www.sentencingproject.org/reports/locked-out-2022-es...