I can't agree with this criticism at all.

I read "surreal" as "it was surreal how whole-heartedly they welcomed us" as opposed to "hiking with your coworkers is a totally surreal, bizarre experience." The surrounding context doesn't support your interpretation at all: the blog post is about how well he was treated, not how strange the experience was.

    That didn’t sound like you, it sounded like something you heard e.g. 
    “open source is good, closed source is bad”

Wow, what? Accusing him of parroting others' opinions is just weird and again, maybe you're right (I can't read the author's mind) but there's nothing else in the post to support this.

    Your criticisms and defenses of Goldman Sachs feel inauthentic 
    because you haven’t experienced much outside of Goldman Sachs.

How many years should somebody spend in the industry before it's okay for them to share their thoughts? 5? 10? 20?

It would be an entirely different story if the author was misrepresenting himself, but considering the post is entire

    Consider not bringing up “drama” if you don’t want to share it 
    with the readers.

I think his brief mention of this and the other minor downsides is precisely what helped this article feel so authentic. It gave me what felt like a balanced picture of life at Goldman Sachs. Leaving out the actual content of the "drama" is 100% appropriate, for a variety of reasons.