It's not mustache-twirling villainy, it's just having a fragile ego and being pissed at a dig at you, which is common across all sorts of people, managers included.
That makes no sense whatsoever. Blizzard used it in an ad campaign "before, during, and after I was separated". It's not like the text was secret.
A simpler explanation is that an aggrieved party is not giving us the whole story. General advice: Be wary taking sides in nasty breakups even if (especially if) you want to like/dislike one or the other.
It's good advice when one person is pissed at another person, it's less good advice when that line of disgruntled people stretches down the block and around the corner.
It's naive to assume good intentions when one party has a well-documented, multi-sourced history of behaving poorly.
And a very simple explanation is that the people who got pissed at it weren't the people who worked on the ads, and even if they ultimately gave high-level approval for them, didn't notice the minutia at the time. Maybe the parts of it they had issue with weren't the parts used in the ad. "Back to the office" and "Another Yacht" could have been the trigger words, and they don't appear there.
You're anthropomorphizing a corporation. Blizzard has almost 10,000 employees and god only knows how many of those are managers. I'm sure some of the managers are great and some of them suck, just like everywhere else.
I'm not anthropomorphising anything, I'm observing trends and patterns in corporate culture. I'd be shocked if the kind of corporate culture that has rotted as much as theirs had would not have any petty, vidictive egoists at the top of the food chain.
'Blizzard' the company doesn't have feelings, but people making decisions in it do. I'm not sure why you're steering us into splitting hairs over this.
Sometimes people really do mean-spirited petty things for petty reasons, and it really is "just" that simple and black/white. It certainly seems to me the story is entirely plausible, although of course I can't judge if it's also true, and I agree it's usually best to ignore these kind of anecdotes, but that's just because you can't easily separate the 'true' from the 'more complicated than that' ones.