On a societal level, you end up with camps.
Intolerance often happens in service to some ideal of “purity”. This or that moderate Republican gets the cold shoulder from the national party because their commitment to conservative ideals is suspect. Clamp down on immigration so our language and “cultural values” aren’t diluted. Form a new religious denomination because the others aren’t strict enough with “sinners”. On and on.
At first blush, Purity sounds like such a good thing, doesn’t it? We don’t much like dealing with complication and challenge. We like nice, neat categories. That makes the world seem more comprehensible, because we can now think of it as a collection of abstract categories rather than one big organic amorphous collective.
But ideas and values are improved under conditions of competition and challenge. It’s natural selection at work; just as species become more fit when put under pressure, so do ideas and values. Inbreeding is just as deadly in the realm of ideas and culture as in the ecosystem. In a society where there is a monoculture of thought and values, stasis sets in. Stasis may be comfortable, but we have promises to keep, and miles to go before we sleep.