"Safe Spaces" and "Political Correctness" are not censorship. They are about changing cultural interactions. I'm not a real "supporter" of either ideologies, but I believe its good to be nice to each other.
One of the points in the article was that Democrats are more willing to self segregate from people they have disagreements with on social media. Its not clear if this is a trend that is increasing or not. My guess is that it is. The left has wrapped these bubbles movements like safe spaces in a positive language that makes it acceptable for those in the bubble.