I've only skimmed this, and the content may be reasonable, but the false premise is the same as that of the ubiquitous "why are people surprised" commentary: Strong reactions look like surprise. Sometimes people even say colloquially "I can't believe...". But a reaction's strength isn't necessarily due to surprise - it may just be due to the drama of the subject. If something awful keeps happening, it's good if you don't stop having a strong reaction to it, no matter how unsurprising it becomes. So, it's not surprise in such cases - it's anger/sadness. Unhelpfully, accusations of "surprise" are also an easy way for bad-faith actors to imply naivete. They will even contradict themselves by using the word "outrage" to describe the same "surprised" reaction, under the implication that "outrage" means "unjust/naive anger", when really "outrage" is often the right word, sans that unspoken implication. "Outrage" can be justified, and people can express it when they are not "surprised".

The surprise the article mentions is not directed at the injustice around us, but at the "strange methods employed by the new-left against those injustices. (I"m attempting to summarize the article, not necessarily providing my own opinion here).

The middle of the article is best, when it puts name to the movement and attempts to describe it so it can be understood by a moderate / non-ultra-progressive thinker. In this case, it casts those moderates as people who would otherwise support the traditional "liberalism"'s quests for equality under the law and opportunity, regardless of race, creed, sex, etc etc, and incrementally improving a system created hundreds of years ago by dead white guys. It attempts to describe impartially the ultra-progressive viewpoint that any competition that has a winner should be torn down, since it obviously has systemic biases due to it being created by dead white guys (their words, mostly).

A fun fact related to this is that in Israel, the term "liberalism" avoided the hijack, is used in the freedom sense, and has the same meaning as "Classical liberalism" has in the USA.