Hitchcock likely received bad reviews as commonly as any filmmaker did in his day or ours. Criticism is by definition made in the eye of the beholder: a subjective review.
The thrust of your question appears to be more about "how did viewers react to socially shocking elements" in Hitch's films. That question, I would suggest, is self-answering. Hitchcock wasn't afraid to tug on cultural norms a little bit in order to influence his audience, to make them uncomfortable. The plot itself of Rope (1948) is arguably an exercise in this tactic.
Worth noting that when you reference "Hitchcock's American films", that period is generally considered to be from Rebecca (1940) to Family Plot (1976), well over half of his career. Of those, very likely the worst reviewed of the bunch, albeit something of an outlier, was the domestic comedy Mr. & Mrs. Smith (1941). He never dabbled in straight comedy again.
Regarding Psycho and the references Legion6000 gives in his answer, keep in mind that Hitchcock produced the movie with his television crew. He did this in order to produce the movie cheaply under his own expense since Paramount didn't want to produce the script. I also recall that he wasn't happy with the tacked-on ending of the psychologist's explanation, but I don't have a reference for why. Possible that's from Francois Truffaut's interviews, which I highly recommend reading if you're at all interested in Hitchcock's work.