I was and am a Bernie Sanders supporter and would never vote for someone like Donald Trump; but if you read the full transcript of their conversation, you will see that it was indeed locker room banter and it continued as they were greeted by the Hollywood actress — with her joining in but with a less disgusted flavor and tone.
What he said was dispicable but he is right that it was 10 years ago; if it was the only thing he had said in the last year or so it would not be much of a concern, but on top of everything else well okay then.
However, have you seen the photos in the NY Times of the woman he was talking about at the time? If women do not want to be degraded then perhaps they should be a little more circumspect in how they dress. And if they are not then I don’t think there is all that much room for them to complain.