There’s no need to second guess that it isn’t wise when your opponent lays a trap for you - that is clearly orchestrated by her and the media - to just jump straight into the trap head first. That isn’t a guess at all. He did that with the Khans and now with the Miss Universe nonsense. “No comment” and both stories end with one round of interviews vs. giving them legs for many days on end by reporting his comments then getting more interviews with which to respond to the comments.
Trump is not someone I’m enamored with and that is no secret from the primaries...but he’s now the only thing we have to prevent Hillary being President and we can worry about the concerns we have with Trump again after Hillary has been successfully stopped. Even so, the belief you shouldn’t get roped in by your opponent so easily, nor give an opponent months of a monopoly over the message seen by huge numbers of voters in the air war is a universal viewpoint that would be applied to any candidate taking such a course of action...wouldn’t just be saying this about Trump. Of course, I can’t speak for everyone else making comments. I believe running over the summer a series of ads that were biographical, family oriented, etc. would have given him a more solid footing with people who have only been seen Hillary’s ads painting him as corrupt and dishonest - it would be helpful to more than just tied in abysmal favorability ratings.
If a majority of voters can be convinced to vote for Hillary because of a claimed remark from 25 years ago, then it doesn't really matter, the Republic is already done.