Well, then, since I disagree with what Lincoln did, I guess I can then be said to have taken up arms against him and his cause, some umpteen decades after the fact. Hey, if that’s the case, then I proudly proclaim I took up arms against Lincoln.
My wife’s father, during WWII, drove a truck stateside when he was in the Army. Didn’t haul war materiel, troops, or anything of a martial nature. The only time he ever “took up arms” was when he fired his weapon in basic training. He never saw a Jap, a Nazi, or an Eye-Tie. Against whom exactly, did he “take up arms?” The silhouette at the rifle range? He never broke a code, transmitted any military orders or logistics, trained anybody in combat, or did anything of a martial nature. He served in the military, but he did not take up arms.
I suppose you can say that...if you have no concept what the term means. Lee accepted command of the Virginia forces which started planning hostile acts against the U.S. the day before secession was voted by the legislature. By any possible stretch of the imagination, Lee took up arms in April 1861, some 20 months before he freed his slaves. And not after he freed them, as you claimed earlier.