The difference (imo) is that it didn't impact the average Kerry voter. A draft wasn't instituted to supply troops for the surge, your taxes didn't go up to pay for it, Roe v. Wade wasn't overturned, etc. When Bush was voted in again, there was fundamentally nothing different in your life than a philosophy you didn't agree with, and in some people's cases (not saying yours) it was in large part b/c a bunch of old white guys with (R)'s after their name were in power.
Compare that with the last 4 years. A fundamental decision on health care payment was pushed through by a very shady deal that got a bunch of the House voted out in favor of the Tea Party. Taxes are about to go up substantially on a healthy portion of Americans. Business conditions (in the views of some) have gotten worse, and the election of the President means 4 years more of it. We've gone up to over half the country on unemployment and/or food stamps, while half the country contributes nothing to those programs in terms of federal taxes. The taxes they DO pay (SS/M/M) are 1/7th what are needed to keep funding at the levels they've ballooned to, but no cuts or payroll tax raises are in sight.
I humbly submit that if taxes had gone up 10% to pay for a war that you were drafted for, that you didn't want to fight in and for a President you didn't vote for, you'd have been much more likely to "take your ball and go home" in 2004. Much like people did in 1968.