Not sure what’s such a ‘hard line’ about it, but I think it’s important for the voters to have a reasonably clear idea of what difference the election makes, so that voters can say, “I like those things, so I’ll vote for her,” or “I’m against those things, so I’ll vote for the other guy.”
Or in this case, “I like these things, so I’ll vote for her, and for Dems down ticket,” or “I’m against these things, but Trump scares the shit out of me, so I’ll vote for her, and vote GOP down ballot.”
I know that for a good chunk of the electorate, it doesn’t work this way in practice, but the whole idea of democracy is based on voters making informed choices. And since the media do such a sucky job of informing voters of the policy consequences of voting one way or the other, it’s up to the candidates. And since Trump is a nutcase, that means it’s up to Hillary.
It has the added benefit that if, in 2018, voters are saying, “we elected you, but you didn’t raise the minimum wage, or come through with a big infrastructure bill, and it’s just as hard as it’s ever been to form a union without getting fired,” she can say, "I told you back in 2016 that if you wanted these things, you needed to not just vote for me, but vote in a Democratic Congress as well.
“So again, if you want these things, get me a Democratic Congress, and stop voting for the Republicans who are against all this. We’ve got another election coming up, so we’ve got another chance to make this happen. Let’s do it.”