Bob Dole is 92, his wife is 79. I've never, ever in my life been disrespectful to my elders. It's just not how I was raised. Remarks about Depends or dementia are uncalled for. However, if someone older than I says something with which I disagree, why not comment on it?
Age or military service does not render one immune to criticism if they've said or done something that merits it. One of the biggest local jerks I've known was a POW in WWII. He later became a big Democrat in our town and state. I respected his service and his sacrifice, but strongly disagreed with his political positions and actions.