Both the fans and Blizzard fucked up a little bit. It's both their faults, and here's my reasoning:
Take your personal inspection of Jeff's daily routine and apply it to the general fans of Overwatch, or Blizzard fans in general. Perhaps Jeff fired off a message on a whim, like you said. You know who are also firing off hundreds of thousands of tweets and chats and messages on a whim? Blizzard fans. And not just Overwatch fans, but anyone who looks at any news related to Battle.net. You know how many people visit, say, mmo-champion who don't even play WoW or most other Blizzard games anymore? Lots of people with varying degrees of attachment for Blizzard products and content. Many of them driving home from a long day at work, or taking care of kids, or being kids themselves, as gamers are won't to be. They check their tweets or chats or their feeds, and they see the Fipps original, pedantic post with Jeff's hasty remark below. Then the vocal minorities shout about freedom and how one person's distaste potentially removed a pose from the game (a pose from the game's 'flagship' character, no less), and you have a spiral that nobody can really stop, and should have been a non-issue to start.
Most of these fans are not going to do the digging. A lot of them don't even play Blizzard games on the regular anymore. They aren't PR people, and we shouldn't expect them to be. They are gamers first and foremost, and gamers care about content. And the fans, like Jeff, can send quick messages on impulse as well. And gamers don't like losing content. Ever. Even the smallest, most stupid shit.
I think it's eerily appropriate way to view the faults of both parties. This is an example of one poorly worded message from Jeff, spawning a million poorly worded counter-messages from fans who only know half of what Jeff knows. This is not the fan's fault. The gaff that spawned a million gaffs.
There are silver linings, though. I find it especially funny to see those people 'championing' Blizzard for being so modern and understanding to the various colors and creeds of the world. "Blizzard is so brave for taking down the pose! They're taking a stand on objectifying women!" But according to Jeff's latest post, that's a bunch of bullshit. They were already thinking of changing the pose before anyone complained, for completely unrelated reasons. I hope the new Tracer pose turns out less objective, but more seductive, just to piss this particular group off. That would make me smile a little.
But the fan's reactions were entirely expected, as this isn't the first time Blizzard removed or changed female quotes or models. The community acted like it always has in this situation. Nothing to be surprised about.
I glance at the top right of my screen and see Widowmaker's tits staring me in the face, and wonder why Fipps didn't have a problem with THAT. Have you read Fipp's original comment? He argues Widowmaker's tits are ok to show because she is a character that 'flaunts her sexuality', but thinks Tracer should stay in the kiddy pool because, to him, she acts too silly to be sexy. Like silly/sassy can't ever be interpreted as sexy. This is a dude who comes just a line short of saying that 'Tracer' and 'sexy' are mutually exclusive terms. It's weird. He's ok with Widowmaker because 'that's her character', but as soon as Tracer strikes an even moderately sassy pose, Blizzard is putting women on pedestals and going against their own lore.
It's ridiculous. The entire situation is ridiculous, and the nucleus of this ridiculousness is that Fipps guys' first comment. I think it's bizarre that he saw no amount of sexuality whatsoever in Tracer's other silly, sassy, bubbly mannerisms, but had to single this one out. I bet Jeff is playing darts tonight, and Fipps' name is on the board, getting riddled with darts between shots of whiskey.