That logic is sound enough. Any large movement will involve compromise.

Where it breaks down is when they attempt to later brow-beat the left with the exact opposite argument. "The swing voter may literally vote for Trump if you don't compromise, but you can't similarly threaten to withhold your vote otherwise you're basically voting for Trump." And that's not even getting into what they want to "compromise" on.

Threatening to withhold votes over an issue is a tactic that's been proven successful. It been no small part of dragging the Republican Party right. They just don't want us to do it.