You hit on the key point, profitable. The southern rebellion was in response to what they saw as a threat to their institution of slavery.
Also the south is constantly portrayed as evil for fighting this war for slavery but hardly a word is mentioned of the rape of the southern economy by the north during reconstruction. A travesty from which the south has just begun to recover from in the last 20 years.
Melodrama aside, southern losses were a result of southern actions. When you start a war you cannot decide in advance how it will turn out.
The southern rebellion was in response to what they saw as a threat to their institution of slavery right of self-determination, their state sovereignty, and the relationship of federal to state government, as well as their property rights, and their right to emigrate to the Territories and take their property with them.
After all, a policy of freesoil Territories was de facto an exclusion of Southern planters and whatever other Southern citizens might actually own slaves. That policy made them second-class citizens in their fathers' house, and intended to exclude them from the national patrimony.
You sound like Quick John, or Hanoi John Kerry. Was the war in Iraq the right thing to do? "It depends on how it turns out." The South fought for the right of State's to determine their own internal issues as guaranteed by the 9th and 10th Amendments. It was right, the North fought to forcibly retain the South in the Union. They were wrong. No more, no less!
Thomas Jefferson: "On every occasion...[of Constitutional interpretation] let us carry ourselves back to the time when the Constitution was adopted, recollect the spirit manifested in the debates, and instead of trying [to force] what meaning may be squeezed out of the text, or invented against it, [instead let us] conform to the probable one in which it was passed." (June 12 1823, Letter to William Johnson)
"With respect to the words general welfare, I have always regarded them as qualified by the detail of powers connected with them. To take them in a literal and unlimited sense would be a metamorphosis of the Constitution into a character which there is a host of proofs was not contemplated by its creators."- James Madison