(1) I'm thinking of the time a reporter drove 50 miles and asked a pizza restaurant if they would cater a gay wedding. The owners said that they were happy to serve gays but would not cater a gay wedding because of religious beliefs. This was quickly spread nation-wide earning them death threats. What was not mentioned was that they had never catered any weddings so the chances of it coming up were zero.
Until the people of the Left recognize how much they isolate themselves they will continue to live in a bubble, happy in their ignorance.
The Right can't isolate itself like that. They are constantly exposed to the Left. All they have to do is turn on any mainstream news broadcast, read a major newspaper, or watch late-night TV and they are bombarded by Trump-haters. The Left even leaves its cities and drives an hour or more in order to find people who don't match their values to hold up for ridicule. (1)
And it's easy for them to avoid contact with the other half. They control most media. Their control of campuses is so strict that pro-Trump statements were ruled hate crimes.
When we say that the left lives in a bubble, we mean a mono-culture. Think of the movie about the boy in a bubble who was shielded from contact with the outside world because of a weak immune system. That's how the Left lives. They cluster in cities and, as shown by their reaction to Trump victory in the election, they want to be protected from the outside world. There are stories of women having their hair cut or the color changed because of the election and of people in an organic food store being distressed at hearing Sweet Home Alabama.
It looks like bubbles doesn't in. It's really hard to say that all of that red in-between is a bubble. But that's only part of the reality.
If you look at a map showing which counties were carried by Hillary Clinton then you see small blue patches surrounded by a sea of red.
After being told that they live in a bubble, the left's response has been, "Oh yeah? So do you and ours is bigger!" One of the more prominent versions of that comes from WaPo columnist, Richard Cohen. The argument is that the left is more inclusive and multi-cultural compared to the mainly white Christians who voted for Trump.As with most things about the election, this shows the Left's ability for self-delusion. The bubble analogy fits them far better than it fits the right for two reason.