Let's dig in.
washingtonpost.com/news/made-by-h…
Here's the link to the original at the Wisconsin Historical Society: wisconsinhistory.org/Records/Image/…
But that doesn't make it true. It seems that thanks to the fact-checking by @pashulman & @CleverTitleTK, Wikipedia has corrected its entry.
They're not "covering up" anything. They're trying to get it right.
As I've noted before, the 1920s Klan had a presence in *both* parties:
And if @JackPosobiec had bothered to read the full entry instead of bumbling into a fog of conspiracy theories, maybe he'd have realized that.