“As I said before, he doesn’t go deeply into the historical and legal background”
Well you can’t possibly be referring to “Shall Cromwell Have A Statue?” because that’s exactly what he does do. All he does is discuss the history of secession and it’s legal standing. That quote in your post is from a different essay a decade later.
But if you can produce even a single sentence from “Cromwell” discussing race and/or African Americans I’ll concede that race tinged his position in it.
Of course I’ve read that essay enough times to know that there is absolutely nothing in it like that, and that this is simply you reading an agenda into it. The Left loves to psychoanalyze their chosen targets to explain them away.
And you’re emulating that.
If that's what you think, you don't know the speech as well as you think you do. Nobody would mistake it for a serious legal or historical study. In all his meanderings, he doesn't make a strong legal case for secession. Maybe he didn't even mean to.
He admits that George Washington wouldn't have believed in secession and that by 1860 secession wasn't going to be accepted by the rest of the country. He makes a case that Lee was a decent man who meant well, but not any convincing case for secession or the Confederacy.
That quote in your post is from a different essay a decade later.
You can also look up Adams's 1906 essay, "Reflex Light From Africa" where he says much the same thing about Northerners being wrong about racial equality.
Adams had formed a mutual admiration society with many Southern segregationists. He expressed views similar to theirs, and they praised him for overcoming his Yankee prejudices and seeing the light about race. Their praise made Adams all the more well-disposed to Lee and the Confederacy. That is the background to his speech and it's hard to deny it.
You've found something you agree with and nothing's going to change your mind, I guess, but look around. When we find somebody has said or done something objectionable, doesn't that affect our opinion of him or her? Or do we just wave everything away and go on believing what we want to believe?