Calling Lincoln the "Great Emancipator" gives him too much credit. He signed the emancipation proclamation out of military expediency, and it was explicitly stated that those states that ceased rebelling would be allowed to keep their slaves.

Lincoln also stated quite clearly that he thought Black people were an inferior race and could not be integrated into American society. His preferred solution was colonization to Haiti, Africa or South America.

Pointing out, accurately, that Lincoln was a white supremacist isn't "cancelling" him. It's an accurate statement of historical fact. Not all historical revisionism is bad. Sometimes revision is necessary to counteract fundamentally erroneous narratives, ex. that Black people owe their freedom to Abraham Lincoln, when he would've happily allowed slavery to continue to exist if that were the way to preserve the Union.