Is this sexism or is it just generalization? The vast majority of (white) women I've spoken to from tech companies are recruiters. And generalizations are very useful, in general. I doubt everyone thinks about how much coding knowledge a recruiter would have. At what point is it "sexist" (and, presumably, bad) to assume something given past experiences?
I don't know if you meant for your argument to be applicable to Gayle, but if so... well, it is not applicable. People only knew her gender and assumed she was not skilled because of it.
If ability is normally distributed for a given sex (and the mean of the ability of the same), then it is true that there would be more above-average male programmers than female programmers - just as there are more male programmers than female programmers at any skill level. If you are provided a skilled programmer, they are most likely male. And if you are provided any programmer, they are most likely male. However, If you pick a random male programmer and a random female programmer, the woman is just as likely to be a good coder as the man.
This means that if you are talking to an anonymous person online and they are a good coder, you should assume they are male (if you're going to assume anything). This does not work backwards - if you are talking to a female programmer and you do not know their coding ability, it would not be particularly likely that they are a poor coder.
You keep describing all aspects of this situation as hilarious. It's condescending and not adding anything to your argument. If you're trying to be persuasive, this isn't how you do it.
I don't think it's very impressive that 42% identified it as virtual currency - it does have "coin" in the name, and none of the other options had any relation to coins.