Could just be that you can only run so many campaigns in a row with "If you don't vote for us, it's going to be the end of the world as we know it. And at least I'm not as bad as the other guy." With the exception of Obama's first run against McCain, that's been the pitch for every single election I've ever been able to vote in, as well as a few before it. It gets old real quick, makes them come off as insincere, and doesn't motivate anyone when we're still largely dealing with the same BS issues that we were 20 years ago.
Trying to browbeat people into voting with the same old song and dance has diminishing returns, especially when your candidate is increasingly out of step with many of the voters they should be courting on major issues.
You'll wind up dealing with a bleaker outlook on democracy one way or another. Just see how long the Democrats can cry wolf with "Oh no, the other guy is going to destroy our democracy, and I swear to god, guys, just vote for us one more time and we're totally going to fix it this time." You can only pull this bit so many times before people stop taking you seriously. At a certain point, you have to ask how stupid the DNC can be? This was a losing tactic with Hillary Clinton, it's not looking so great for Biden, but just keep rolling it out every few years, it's bound to start working sooner or later, right? Definitely sounds like a winning move to me. Heck, it's real convincing when that's what Biden ran on last time, and he's not exactly crushing it with his strategy of "I'll just go talk to these Republicans like I did 40 years ago, I'm sure we can reach an understanding like we used to, back when I still wholeheartedly helped pass laws that would lock up minorities."
I'm sure being able to say "I told you so" will make you feel much better if things don't pan out and it turns out you can't just nag and guilt trip people into voting for a candidate that holds views they can't stomach voting for.