The game of trying to determine "who is the guilty sexist" is tiresome. We all say and do mildly sexist things from time to time. I do, you do, women do. Moreover I do not care about Mark Shuttleworth in any capacity other than as an illustration of the systemic bias in this community. You seem to understand systemic bias at least as far as language use, but you seem to think it stops there, that a little gender-biased language isn't worth getting enraged over. Unfortunately it doesn't stop there.
It's actually just indicative of much deeper biasing. Look at any of the numerous threads that have come out of incidents like this. Look at the discussion. it's 100x worse than the initial gaffe. What starts as a matter of language bias (or, well, in some cases uglier concerns such as pornographic slides) rapidly descends into outright verbal abuse. You have men of this community claiming women have developmental, genetic, psychological, spiritual or otherwise innate inferiority in technical tasks. Men insulting women's appearance, sexuality, intelligence, sense of humor and honesty. Men threatening women with harassment and assault. Men cracking jokes about male domination and male privilege. Men telling anyone who dares take issue with any of this to shut up, go away, drop dead.
You do not get to decide via some courtroom logic whether a statement is "ok" or not. There is no point examining the circumstances to tease a plausibly non-biasing meaning out of it. This is an even more tiresome game. Those statements made -- made -- people feel another shove of bias in an already systemically-biased environment. They make me feel that. Any time I'm in the room and someone talks about "software so simple their girlfriend could use it" and "simple enough for Aunt Tillie", or "coding like a rockstar" and "manning up", or any of the horrendously biased statements made in the now-numerous threads about this topic elsewhere. Those reinforce the bias. I feel it. Enough people feel it to be talking about it. Deal with that fact, don't tell us how we feel.
It doesn't matter what was intended in Shuttleworth's case. Intention is not effect. When you intend to make a funny joke and nobody laughs, do you try to argue your audience into laughing? When you intend to ship an appealing product and nobody buys it, do you try to argue your market into buying?
You do not get to argue someone out of their feeling, their response. You might not care, that's your choice. But if you care, the habits of speech and conduct need to change. More than that, the underlying attitudes revealed in the ensuing conversations need to change. If you don't care, your loss. Continue to lose most of the women and a chunk of the men who are too annoyed to stay.