I think that perception is relative and personal; so mostly I allow others theirs.
For example:
Pooh to an adult human is disgusting...to a baby it is play dough....to a dung beetle it is a palatial home.

But if someone insists on trying to make their perception the only one that is valid, with a light heart, I might ask them what the color of the sky is in their world. That usually causes them to pause or slows them up a bit.

If they persist beyond that, there is always this good line:
"Sometimes it is better to remain silent and appear the fool than to open one's mouth and remove all doubt."

In the end, it usually isn't worth debating with someone on differences of perception...especially if their's is so limited that it has needed to be pointed out. Some are just so blind, that they just can't see even that.

I have found that to smile sympathetically in their direction and then to carry on is the best punctuation to such conversations.