There are posters on this board who consider Robert E. Lee to be the equivalent of Heinrich Himmler. They’ll probably show up on this thread.
Growing up in rural Iowa public schools, the memory of Robert E. Lee was treated with the utmost respect. This was in Iowa, which contributed more in Union manpower per capita than any other state. Seems like any demonization of Lee is historically recent or was limited to certain quirky locales.
Most American soldiers respected Field Marshal Erwin Johannes Eugen Rommel. He was even called the Desert Fox, out of respect. It is well known that he treated his prisoners of war humanely, and he ignored orders to kill any captured Jews. If I can have respect for a German soldier like Rommel, why the hell can I not respect Lee?
No, there aren't. There are a few who think of Lincoln as something close to Hitler, though.
The point the posters you criticize are trying to make may be that the idea of an American Army officer turning his back on the country to lead an army against it isn't something that we can wholeheartedly celebrate. It's at best morally very ambiguous, and perhaps worse than that.
If something like this happened today, and the former Superintendent of West Point took up arms against his countrymen we wouldn't just celebrate his character and victories, would we? We'd wonder about him, maybe condemn him. You don't have to. But it would help if you recognized that there's more than one side to the question.