The phenomenon of "safetyism" that you describe is unfortunately very real and widespread, but I reject the idea that this is a problem, "of the left". The fact is that the people who suffer from this mental disease don't have the intellectual capacity or knowledge of history to have any coherent ideology. The idea that there exists a binary, left/right paradigm is, in itself extremely questionable. Its not useful to try to place mentally fragile, intellectually crippled people whose behavior is entirely governed by perceived cues from their peer group on a "political spectrum". One of the people you cite in your article, Lee Fang, is an excellent example of someone who is actually, "on the left" (as it is generally understood to exist) who was attacked by this mob of apolitical reactionaries because he dissented against their dogma.
Unfortunately, in the United States, people are dumb and getting dumber. At the end of the day, you cannot have a functional, self-governed society filled with stupid people. Its not an easy problem to fix.
The majority of people who advocate for "Safe spaces" are on the left. I have yet to see an example of someone on the right who asks for a safe space... not that there isn't. These aren't absolutes, but generally true with possible outliers. I didn't say it was everyone on the left, int eh second sentence: "some lefties". I'm not right or left, I'm against masters/rulers of any political party.