Except that a person who is literally blind found it disrespectful.

People say all sorts of stupid stuff that they don’t intend to be disrespectful but which is. When it’s pointed out by someone the appropriate response is to change your behavior, not double down and make excuses.

Here’s another example: In my state (MN) it’s not uncommon for (largely) women to refer to themselves as hunting widows when their spouses go away for the weekend to hunt during the season. They say it as a joke but it’s disrespectful and diminishing to actual widows. How do I know? I’ve been widowed.