I don't think Lincoln intended to propose that a minority has no right to fight back against such a revolution.
Or do you propose that if liberals manage to cobble together a 51% vote to get rid of the Constitution, the rest of us have no right to resist them?
BTW, your 6% number is wildly inaccurate. That is the percent of the white population that held title to slaves. Of course, when a family owned slaves title was held by the head of the house, but we wouldn't say his wife and children were not also slaveowners.
Actual percentage of white families that owned slaves in 1860 in all slave states was 26%. The percentage ranged from 3% in DE to over 50% in SC.
http://www.civilwarhome.com/slavery.htm
And lol at you trying to stretch the numbers. If having one person in a family own slaves makes everyone else like slaveowners, then when I was little living under my father's roof I was a house owner. I profitted from it for a short time in my life, so I must be just like an owner. Never mind that I didn't actually spend any money on it or that I didn't get to keep it when I got older, I owned the house too!
Also, don't forget about the free blacks who owned slaves too. :-)