I'd say that your argument is too reductionist. Without addressing one single issue, Secretary Clinton is not deserving of Senator Sanders' voters support in the general? Why can't there be other issues? For example, what if a Sanders supporter is a diehard supporter of single-payer healthcare and doesn't care about her speeches? Hypothetically, Clinton comes out in favor of a transition to single-payer healthcare. Would she then be open to the support that Sanders' voter?
Further, I reject the construction of your premises. First off, the first premise is a badly written proposition, if there is one. Are you saying that Sanders derives his support from people who want to get money out of politics? What does "get money out of politics" even mean? Sanders has raised about as much money as Clinton. So is it that the money is evil? Or is it that it has undue influence? If it's about undue influence, the burden is on Sanders to demonstrate how campaign contributions have influenced Clinton's policy positions as an elected or appointed official. Is it that campaign financing requires greater scrutiny and accountability? On that front, Sanders fares worse than Clinton. In the last FEC report, Sanders had 270 pages worth of documentation of foreign donations and donations that exceed the federal limit for individuals. Clinton's report had 3 pages and it was mostly failing to expense travel correctly on the form.
C1 can't be derived from the premises you've laid out. Secretary Clinton's speeches were not "campaign contributions." Further, I'd present an alternative path toward whether someone has earned the right to unite the party under the banner of democratic politics. It would be if that candidate wins the primary for the democratic nomination for president.
On C2, I'm going to try to work within comment rule 2 and not be rude or hostile. I'm a progressive democrat who supports Secretary Clinton. I support Single-Payer healthcare. I support public financed campaigns and greater accountability. I want better privacy protections and worry about the fight against encryption. I disagree on some of Clinton's platform just as I disagree with planks in Senator Sanders'. I empirically reject your conclusion that my voice as a progressive democrat is silenced by Clinton's success. I'm involved in my party. I speak with my elected representatives pretty often. If you believe that the only way to have your voice heard is through your vote, then you're failing to support the progressive movement with the tenacity it deserves. Change is hard. Change is messy. Change requires compromise.
Now, while I've addressed your premises, I've mostly critiqued the shoddy construction of your argument. Let's give you the benefit of the doubt and create a better constructed argument. If you disagree with my reconstruction, please correct me.
I still dislike the argument because all we're doing is demonstrating that a person does not deserve support until X obtains and we aren't making a case that a person deserves support if Y obtains.
Anyway, my objection to this reconstruction is against Premise 4. Leaders generate political capital through building social capital. This political capital can be leveraged for a self-interested progressive agenda that goes contrary to the perceived interest of the group because of a trust in the relationship. I have a personal friendship with one of my employees the predates his employ with my company. I am still committed to holding him accountable to his performance standards despite our history.
If I still have your attention, which I really shouldn't by this point, this post is way too long... I figure in for a penny, in for a pound.
I want to provide you with my interpretation of the Democratic party. I've been a democrat for my entire political life. I was raised by a Reagan Republican, but my being a democrat wasn't an exercise in rebellion. I was pretty moderate as a kid. I was unsure of my feelings on abortion. I supported only civil unions. I didn't know how I felt about affirmative action. But I knew I was a democrat. Now that I'm an adult in the midst of my career, I'm a fairly liberal progressive. I still am a democrat. The reason is because the Democratic Party is a coalition. It is organized on the premise that our diversity makes us stronger. We're diverse in religion, sexual orientation, racial and ethnic background, gender identity, geography, income-level, age, education-level, and ideology. Because of this diversity, our various constituencies have different (and sometimes competing) priorities. The leader of our party ought to be a person who can lead a wide coalition. The Republican party is in shambles right now. They embraced conservative purity tests and a zero-tolerance policy for compromise to appease the Tea Party. The best strategic move progressives can make is to stay involved in the democratic party regardless of nominee and push for it to be as big a tent as possible. Welcome the disenfranchised Republicans. Welcome the moderates and centrists. It's okay if you're unsure on abortion, trade, net-neutrality, and gay rights. As a coalition, we believe in working together to move our party forward. Let's learn from this mistakes of Republicans and reject purity testing in our own party.
How does this connect? I may think that Bernie Sanders is an inept, carpet-bagging, snake oil salesman that preys on the gullible, but I have no question that he is trying to make the country a better place. Should he become the nominee, I'm going to fight just as hard for him as I would for Clinton (a machiavellian opportunist who is out-of-touch with the realities of the information age). Because I'm a democrat. And the person who deserves my support is the person who my fellow democrats nominate.