No, I agree with you in much the same way I agreed with Pigeon earlier when he said that the people don't give a shit about SCOTUS. They don't. We're on the same page here.
The Democratic base doesn't give a shit about Garland (sorry Garland). What the base cares about right now is seeing our elected officials fight as hard against the Republican agenda as the Republicans spent the last decade fighting against the Democratic agenda, as well as fighting against common freaking sense.
So the argument doesn't really matter. To be fair, all of these arguments have some level of validity (unlike the bullshit Republicans tend to align behind), but at the end of the day they're all just excuses to achieve the real goal: oppose Republicans, keep the base energized, and protect your seats. Pick an argument, coordinate, get behind it and stick to it like glue.
The main point I'm making is that Democrats need to get better at uniting behind a strong message, whatever that message is. Because as of now they're total shit unless that message is "Hope...or something."