For context, this is from the trailer from the Divided States of America spin-off miniseries (from the Kaiserreich universe from Hearts of Iron mods). It casts the Combined Syndicates of America (the socialist faction in the civil war) in a mostly negative light because something something warcrimes something something revolution is bad.
To add to what others have said, the Lincoln head is pretty much in line with the lore. The CSA see themselves as the latest (and most radical) iteration in the pursuit of actual "liberty" in American history, as well as the eradication of liberal democracy's many contradictions, which naturally leads to Socialism. Yes, it's lib and all to try to reconcile a settler-colonial project like America, but given that they're burning said settler-colonial project to the ground and building on top of its ashes, it could be worse. There's also the pragmatic value since outright disowning America would only embolden reactionaries.
It's not that weird when you look at our history, anyway. Just look at the CPUSA in its relative prime. Even the Bolsheviks didn't make a clean break from Russian patriotism and history. Why else would they wear those silly-looking hats in the Russian Civil War?