I think I've figured it out:
You can add an adjustment preset to multiple photos without lifting and stamping, even if it involves sliders or other analog variables, but not an adjustment that isn't a preset, which will just be applied to a single photo.
So, to add a curves preset to a whole bunch at once, you create the edits you want on a picture, then go to the presets menu, and select "save as preset". Once you do that, you can select multiple photos, then pick "add adjustment preset", and it'll apply curves or whatever to all of them with the settings you'd used when you saved it.
The challenge for me was that it's not terribly intuitive that "Add adjustment" won't apply to more than one photo, but "Add adjustment preset" will.