Keith Ellison and his defenders spent a lot of time lying about his past with the Nation of Islam, a racist hate group that believes Jews are evil, white people were created by a mad scientist and will be exterminated by UFOs. The most popular of these lies was that he merely helped organize the Million Man March. That lie has conclusively come apart with evidence from his past, including accounts from the Nation of Islam. Ellison defended anti-Semitism and participated in ugly and hateful events. He didn't do this for five minutes on some Sunday morning, but for quite a few years.
Not only did Ellison know what Farrakhan stood for, but he defended him against charges of bigotry.
The fallback defense has been that it was a while back and Ellison had disavowed Farrakhan and we all ought to move on. There are two problems here...
1. It's highly unlikely that a member of the KKK would get this same kind of pass (not to mention the media wall of silence about his past that Keith Ellison benefited from) especially...
2. ... if he kept blowing dog whistles and echoing versions of his old hateful views
Keith Ellison didn't completely break from his past. He moved from the Nation of Islam to a more mainstream Sunni Islam, while maintaining hostility to Jews and pushing Islamic Nationalism in more covert terms. The speech leaked by IPT which caused the ADL to back away from their support for Ellison is a typical example.
Keith Ellison is still layering suspicion and hostility toward Jews through his rhetoric, while insisting that there's no bigotry there. This is exactly what he was doing in his Nation of Islam days. Even back then Ellison was clever enough not to scream, "The Jews are the Devil!" the way some Nation of Islam figures did.
Instead he blew dog whistles. He tried to make Nation of Islam bigotry seem sensible and credible. Now he's trying to make Islamic bigotry seem credible and sensible while pandering to bigots.
Ellison has changed affiliations from the Nation of Islam to Islam, but he hasn't changed his core attitudes and views. Or his tactics.