Matthew 7:6 International Standard Version (ISV)

6 “Never give what is holy to dogs or throw your pearls before pigs. Otherwise, they will trample them with their feet and then turn around and attack you.”

What is holy? Pearls are an example. It may have represented as something expensive those days.
However, is the pearl sacred? The value of things changes according to people and the times. There is nothing formerly sacred. It may seem to be holy because people believe it so.

The background of belief seems to be on human tradition, culture, and customs. Believing can make it sacred.

In Japan, there is a proverb, "A cat shows no interest to koban (old oval shape money of god)." It means that because the cat doesn't understand the worth or value of gold money, it cannot show interest in it.

The big difference is that dogs and pigs get angry and attack when they get holy things or pearls, but cats stay calm and show no interest.

Jesus may have intentionally told people so because dogs and pigs here represented people who hated to listen to Jesus.

Jesus described that his teachings were sacred like pearls, and even if he told it to people who did not understand them, they would trample them with their feet and then turn around and attack.

There were indeed people who did not accept the words of Jesus and opposed his teachings.

However, expressing such people as beings like dogs and pigs is contrary to his teaching, "Don't judge people. Love your enemies." Is it against his words?

Nowadays, it is not allowed to make a judgment by personal thought, or to rule out that he or she is not worthy of living.