Yes, your comment may get Sarah off the hook, but I'd probably feel even more offended by that comment than by the boss' request.
If she has the courage to display any disdain over your overtly sexism comment though, perhaps the boss would take (mental) note.
At the same time, the boss may not even be aware of the sexism in the initial request--he/she may rationalize the request/decision after-the-fact, even if it were made in a sexist light at a subconscious level. In that case, that comment may end up offending both the boss and Sarah.
(And yes, women in management sometimes are more sexist against female subordinates than male counterparts.)
If you follow up your comment with an apology and an offer to take notes, however, everyone will feel better.
His turn of phrase suggested to me that said overtly sexist common would me delivered with sufficiently dripping sarcasm to make it clear he wasn't in favour of the idea.
I think I might say "yes, boss, because the possession of a penis renders one incapable of note taking, obviously" instead but that's more about the turn of phrase of my sense of humour than anything else.
If you worked in a "traditional" corporate environment, you would know why it's offensive. General rule of thumb is, don't say it if you wouldn't say it to your mother. I certainly wouldn't say that to my mother.
Edit: to elaborate, corporations aren't concerned with being labeled as sexist. They are worried about being sued because of sexism, because it's one of the toughest kinds of corporate lawsuits to defend against, and one of the most lucrative kinds of lawsuits for the plaintiff. (IANAL though)
If she has the courage to display any disdain over your overtly sexism comment though, perhaps the boss would take (mental) note.
At the same time, the boss may not even be aware of the sexism in the initial request--he/she may rationalize the request/decision after-the-fact, even if it were made in a sexist light at a subconscious level. In that case, that comment may end up offending both the boss and Sarah.
(And yes, women in management sometimes are more sexist against female subordinates than male counterparts.)
If you follow up your comment with an apology and an offer to take notes, however, everyone will feel better.