"[...]
Truffaut. Would you say that Stewart Was merely curious?

Hitchcock. He`s a real Peeping Tom. In fact, Miss Lejeune, the critic of The Observer, complained about that. She made some comment to the effect that Rear Window was a horrible film because the hero spent all of his time peeping out of the window, What`s so horible about that? Sure, he`s a snooper, but aren`t we all?

T. We`re all voyeurs to some extent, if only when we see an intimate film. And James Stewart is exactly in the position of a spectator looking at a movie.

H. I`ll bet you that nine out of ten people, if they see a woman across the courtyard undressing for bed, or even a man puttering around in his room, will stay and look; no one turns away and says "It`s none of my business." They could pull down their blinds, but they never do; they stand there and look out.
[...]"

Hitchcock by François Truffaut, A Panther Book, 1968