[asoneth]

I've heard the same, but the story was apocryphal.

Specifically that when they needed to decide which paste style should be the default "Paste" operation it was a combination of user research and a bias towards novice-friendly defaults that led them to pick paste-with-formatting as the default and paste-as-plain-text as the alternative.

I'd also be interested in seeing the actual research and design rationale.