Just because you agree with something doesn't make it right (duh). Most political problems are multi faceted and affect multiple things.

Is terrorism a threat? Yes. Should it be stopped? Yes. Is a "muslim ban" the most effective way to combat it? I don't agree that it is. I have yet to see any compelling reasons as to why. Similar to how building a wall won't stop illegal immigration: is illegal immigration bad? Yes. Do I want to see it stopped? Yes. Where I tend to disagree with Trump are these grand gut-feeling gestures that I see as reckless on issues I think everyone, conservative or liberal, wants to see addressed. It's very compelling to adopt a simple narrative and think that some hero is going to sweep in and solve everything with broad strokes. But reality is much more complicated than that. I have a very strong feeling that in four years illegal immigration and terrorism are still very much going to be issues - hopefully not worse than they already are.