That is more than likely the case, although keeping slavery alive was definitely a major issue. If Britain had managed to fund the South, under the premise that Britain was largely dependent on the south for Cotton, we may still have slavery today, for all we know.
But the Confederate Flag, and the statues of the confederate leaders is a symbol of a moment in time for this country. Almost anyone who realizes that the south actually lost the war 165 years ago associates those symbols of oppression and slavery. It's one of the first things they think of. That, and the General Lee from the Dukes of Hazzard.
When you look at a statue of Washington or Jefferson, slavery isn't usually one of the first things that crosses your mind