I just don't see how it's disrespectful. To me, this method is significantly more disrespectful.
In my mind:
I can be alone with anyone because I would never cheat on my wife = Respectful
I won't eat alone with someone of the opposite sex because i know I'd cheat on my wife the second i had the chance = Disrespectful
Maybe I'm over simplifying it
your way of looking at it is just as valid. it's a security, comfortability thing. Flip it the other way and ask yourself if someone of the opposite sex told you they didn't feel comfortable being alone with you because they think it to be disrespectful to their significant other, how would you respond? Or put yourself into the significant others'. Everyone will have a different answer for each situation. And trying to police others' comfortability with a situation is rarely a smart move. Especially when it's a situation that isn't that important, and one where a solution is easily found (e.g: have more people around).
My problem with this entire situation are the responses trying to defend Pence's original position, which are almost uniformly stupid.