Source? Your link doesn't say anything about basic edit suggestions.
Looking at the emails [0], this appears to be strong editorializing (much of it far from clearcut) for what (I believe) is an opinion piece.
[0]: https://greenwald.substack.com/p/emails-with-intercept-edito...?
It looks like a tantrum to me.
As you say, he was the one who first began displaying the unprofessional behavior. He probably should have just sent like half of his follow-up email (the citations of the email compared to the article) and given them a chance to reply. But I also understand why he felt he was being unduly pressured and why staying there wouldn't have been wise for him.
I am also very familiar with the editing process. I'm not saying that the editing suggestions are beyond what you would ever see in an editorial context, but I would never characterize them as "basic edit suggestions."
Much of the quibbling in the edits to me suggests ulterior motive, like the rejection of the idea that there has been "suppression" of the story (there obviously has).
And if you're familiar with the editing process, you'd know that edits are not always completely apolitical, I know people who have been asked to make edits for political reasons in major national publications.
I think it is hard to claim this is just equal editorial scrutiny, given the publication of multiple false claims around the Hunter Biden story (ie. "very likely to be Russian disinformation", etc.).
> the editor is nothing less than professional/polite
To me, I don't necessarily always side with the actor who appears to be more professional, though I do agree that Greenwald comes off as rude in the email.
Seems like a temper tantrum to me, even if the journalism is legitimate. It could very well be these claims are clickbait for the journalist to strike out on his own without the publisher.