About which assertions?
Unfortunately failed attempts are written about much less than successful ones, so I have not found in-depth discussions on the net about "compensated emancipation" in the U.S., though that's the term to search for. I have found a few references to specific attempts though.
http://www.mrlincolnandfreedom.org/inside.asp?ID=8&subjectID=2 lists an attempt in 1847 (unclear what territory it covered -- may have only been Pennsylvania) and one submitted by Lincoln in 1849 (limited to DC). Neither succeeded.
http://www.mrlincolnandfreedom.org/inside.asp?ID=35&subjectID=3 covers some of the actions during the war.
For slavery being the only real cause of the civil war, well, to me it's pretty clear that without slavery there wouldn't have been a civil war, and that no change that didn't also eliminate slavery would have eliminated the civil war, though some may have delayed it. There are two nice blog posts more or less on that topic: http://www.theatlantic.com/national/archive/2010/04/the-ghost-of-bobby-lee/38813/ and http://volokh.com/posts/1218531359.shtml
http://www.dailykos.com/story/2010/4/13/856804/-To-Those-Clueless-Wingnuts-Who-Claim-That-SLAVERY-was-NOT-the-Main-Cause-of-the-CIVIL-WAR... has a nice selection of the actual declarations of secession. More can be found with a bit of searching, e.g. http://sunsite.utk.edu/civil-war/reasons.html
I'll try to add a bit more later.
About which assertions?
Your comment was simpler when I responded. I have edited my response to quote the part I was responding to.
I think your first two links address my question, though I will have to look at them in more detail.
What do you believe that most people on this site don't?
I'm especially looking for things that you wouldn't even mention if someone wasn't explicitly asking for them. Stuff you're not even comfortable writing under your own name. Making a one-shot account here is very easy, go ahead and do that if you don't want to tarnish your image.
I think a big problem with a "community" dedicated to being less wrong is that it will make people more concerned about APPEARING less wrong. The biggest part of my intellectual journey so far has been the acquisition of new and startling knowledge, and that knowledge doesn't seem likely to turn up here in the conditions that currently exist.
So please, tell me the crazy things you're otherwise afraid to say. I want to know them, because they might be true.