How can I disable a wall switch and leave the circuit always on?
That is correct. If those are the only wires in the box you have a typical switch loop:

You'd simply nut the two wires together, reinstall the switch and plate (or a blank plate) and be happy.
However, that switch might come in handy as it is. You could also use one of the small retainers that go under the lower plate screw to lock switch position. That's reversible with less effort and they're available at hardware stores or online.