Smoothing is orthogonal to high frame rate. You shouldn't upscale lower frame rates by making up frames (essentially tweening). It adds latency (boo) artifacts (boo) and reduces fidelity overall (boo).
If the source happens to have more frames, then show them of course. But otherwise I'd prefer to see the same frame again for the extra 1/60th of a second.
I see their point though. Like UAC alerts being a janky experience that forces developers to fix things, watching interpolated 60fps is a janky experience that gets you used to 60fps so you won't react to it with an ingrained stereotype.
Believe me I've tried. It's good for sports, meh for TV shows, and horrible for films or anything filmed (which includes a lot of scripted TV.) I don't think anything but 24 (or 23.976) fps will ever look correct to me for movies.
If the source happens to have more frames, then show them of course. But otherwise I'd prefer to see the same frame again for the extra 1/60th of a second.