I agree with you. If one can get past the word "slavery" in the causes of secession there are many reasons to be found for secession.
It has always been my position that secession and "the war" were two separate events. In other words Lincoln did not send his fleet to Charleston and Pensacola because of the act of secession. He sent them for the purpose of holding them in order to collect "revenue." I believe I posted the docs abbot 3 months ago.