I agree with you in boiling it down to: Democrats have failed the people because they haven't done enough good things, while Republicans have failed the people by actively doing terrible things.
So my conclusion is that yes, both parties have done terrible things, and I agree that Democrats haven't gone far enough on most issues I care about, but the GOP is actively going against the things I care about.
It's an easy decision at the ballot box, and it is an easy decision for me to do more than simply vote. Voting is the lowest bar for participation in a democracy.
Sorry, I didn't articulate my thoughts well: I meant that when I CTRL+F'ed the PDF searching for "dissent", the second of three places in the PDF that it "finds" the word dissent is literally behind the word "concurring" in "SOTOMAYOR, KAGAN, and JACKSON, JJ., concurring in judgment" on page 15 of the PDF.
I also don't have legal training to dissect most of what's in there, but I find it interesting that dissent is embedded in the PDF behind the title to their opinion.