It's evident from this that you pretty much have no idea what you're talking about. Let's address it point by point.
1) "The North" was not a monolithic entity. There were various political factions at play and some were in fact pro-slavery (and, incidentally, anti-war). Notably, the banks in the Northeast, which had essentially grown up financing the expansion of slavery into the Deep South and Mississippi Valley, actually attempted a capital strike rather than financing Mr. Lincoln's war, which they saw as basically insane.
The real force of anti-slavery politics came from the bulk of smallholders from what's now the Midwest, and they were against slavery mainly because of their political/economic interest in limiting the power of the Southern slaveholders. Many, perhaps most, of the Midwestern farmers were after all selling foodstuffs to cotton plantations in the Mississippi and Deep South and getting screwed on the deals due to the economic power of the slaveholding class, which Lincoln and the Republicans argued was due to unfairly stealing the products of other people's labor (Lincoln also argued this about the Northern class of merchants and bankers). This was the basis of the free-soil movement that eventually became the principal political force in the Republican Party, and it had nothing to do with political opportunism or European intervention in a war that no one really knew was coming until it was almost happening.
Then of course there were the radical abolitionists, and it was the war itself that actually made their ideology politically dominant, as it increasingly became clear to the Federal government and the military that emancipation was a military necessity, an aspect of a total war strategy designed to bring the South to its knees socially and economically.
2) The South looked like it would be isolationist is another laughably ignorant statement.
I would suggest picking up this book if you have any interest in the matter:
http://www.hup.harvard.edu/catalog.php?isbn=9780674737259
The truth is that the Slave Power orchestrated a great deal of territorial expansion for the US and had imperial designs for much of the land around the Caribbean (including Cuba). The Mexican War in particular was decried, more or less correctly in my view, as a straightforward land grab designed to increase the political power of the slaveholders.
Inno in that sense is half-right- the North had an imperial project, but the South did too, an imperial project that has been fairly obscure for the simple reason that as soon as the South lost, the Lost Cause historiography that emphasized the points you're trying to argue here became dominant - the South was just defending itself, the war wasn't really about slavery, and on and on.
3) Finally, I at least am certainly not hailing the Union as heroes, though I do think the South were unambiguously devils. For your last question, you again just don't know what you're talking about. It was during the Civil Rights era, the 1960s, that the dominant Lost Cause, Southern-friendly historiography of the Civil War was overturned by serious scholarship. Twenty years ago people with a clue were still speaking as though the South fought for slavery because it did. And I dunno, I'd say the debate as a whole isn't really low-level, there has been a lot of quality scholarship that's come out recently, if
this debate seems poor quality perhaps it's because people who are utterly ignorant of the topic keep feeling the need to stick their oars in the water