I think it was also (to a certain extent) a sign of the times. As the censorship on sexual content was relaxing I can’t help but think that film makers used it as an excuse to get some tits on show and insert some sexual content for purely titilation reasons. I will bow to Scherps’ superior knowledge on the catholic roots angle, he knows far more about this topic than I do, but you can’t escape the fact that this kind of cavalier attitude towards rape was also present in U.S westerns of the time.
Waterhole #3 is a perfect example of that. James Coburn rapes Margaret Blyes character at the beginning of this film and it is considered all good fun which she fundamentally enjoyed. I find this one of the most distasteful examples of such stuff ever personally. But Clint Eastwood also rapes someone near the beginning of High Plains Drifter as I recall, and he remains the hero of the piece throughout; albeit in an avenging angel capacity.
Thankfully we don’t see too much of this stuff anymore.