It sounds to me like she intentionally phrased it so it could apply to both of them, and maybe be interpreted to apply to the several news outlets owned by billionaires as well (fox news, washington post, etc.). It's a weirdly common feature of our dystopia at this point, and I think that's what she was expressing exhaustion with. So while she may not have initially intended to exclude Musk, I genuinely think it wasn't just about him, and phrasing her reply in this way was funny and pretty much guaranteed to get more people to see the message.
Not only that, the exchange makes the point even better than the tweet alone. The fact that one of the billionaires in this category showed up on his own to confirm the truth of it. If she planned it that way, this is what actual 4 dimensional chess looks like.
Jesus you people. Hey guess what? I don't give a flying fucking shit about likely kiddy diddler Elon Fucking Musk. That doesn't mean I'm going to be a drooling dumbass who claps every time someone makes a pathetically low effort jab at him. AOC's response here is so fucking transparent that she somehow winds up looking lamer than Elon Cheeseface Musk. That's how pathetic lies like this are.