In general, I grudgingly agree with your cold analysis- it’s true, a large segment of the opposition to Trump can only make sense of, and respond to Trump on a visceral level: Trump Evil!
However, that doesn’t preclude him from being evil.
As for the label “Resistance,” it comes from the same gut-level. For me, it spontaneously came to mind as I watched the Trump administration unfold. I thought of the French Resistance. You underestimate a movement which has only been coalescing for 3 months; it’s width and depth are as significant as its growing fervor. I wouldn’t count on it as being ineffectual. A storm is brewing.