Wisconsin[1] and Michigan had turnout in the low 70s, not close to 100% as claimed. Turnout was high, but only a few points higher than recent years.
There legitimately are some batches of votes where Biden got close to 100% of the votes due to segregation and mail-in votes being counted separately. The mail-in votes in a predominately black area should be expected to be close to 100% for Biden. It would be suspicious if they weren't.
[1] https://www.usatoday.com/story/news/factcheck/2020/11/05/fac...
[2] https://www.freep.com/story/news/politics/elections/2020/11/...
Consider that Trump won the largest share of non-white voters of any Republican in 60 years, including historic numbers of Latino and African Americans.
[1] https://www.whitehouse.gov/briefings-statements/remarks-pres... [2] https://www.nbcnews.com/news/nbcblk/black-men-drifted-democr...
The parent comment noted that in some heavily black PA districts, there were few/no registered Republicans, and those few that were there presumably voted in person due to the GOP spending months trashtalking mail-in votes.
In-person results were tabulated on Tuesday. Under recent PA law, mail-in ballots couldn't be counted before Tuesday. As Democrats generally vote mail-in in higher numbers, this meant that the mail-in ballots would be overwhelmingly Democratic with few if any Republican ballots.
> Eighty percent of Black men supported Joe Biden, down slightly from Hilary Clinton’s 82 percent