From what I seen and read, even though people might not see a "great difference between the candidates", and you might not think the dems selected are progressive enough, but the end result of the last 40 years has been that every Republican administration has been totally fucked in a number of ways that the interceding Democratic administrations just haven't been.
Carter promised to hand back the Panama Canal to Panama, then Reagan happened, and during Bush I, they invaded Panama (dubious motives / timing, also a test-run for Iraq War I), then Clinton comes in, and honors Carter's agreement. I'm kinda betting a Republican would have reneged. Then Bush II and Iraq War II, then Obama. I can't see the Carter, Clinton, Obama gang being anywhere near as bad as the Reagan, Bush, Bush, Trump gang by a longshot. The level of corruption and secret dirty wars that have gone on under those guys, and courting international war criminals as buddies. Maybe you can dig up a few examples of that with Democrats, i don't know, but not the constant revolving door the Republicans have for this stuff.
Sure, there are common things that are fucked about both of them, but the differences are stark too. That's because it's not just the candidates, it takes a team to run the government and when you have a Democrat in power, they will draw from the wider Democrat ranks to fill positions, and there is also politicking in a good way when this happens - negotiation between the wings of the party as to whom is running what.
Clinton may have sucked in a number of ways, but you'd have paid parental leave by now if she was elected, along with probably a number of Obamacare expansions and something being done about global warming. It's laughable to say that you can 'um and ah' and say she would have been equivalent to Trump in any recognizable way.