Slarti... if you're referring to Ovaries' comments, she is merely repeating things that men have said about contraception on this board and elsewhere. So yes, I'd agree they're sexist, but not that ovaries is being sexist. So, not criticising men for what they might say, but for what they already have said
Ovaries was the first post about a new technique but rather than comment on that she chose to add a glib comment about what might have been said in the past.
I know it was a Daily Mail article and Daily Mail comments and ,despite so many DM links so many MNetters never read the DM, but none of the comments I saw made that point. The vast majority thought it was a good idea- not necessarily from honourable reasons in most cases - from the prospect of being free of being "trapped" by contraceptive failures.
Personally if I really wanted to avoid getting pregnant I'd stick to the pill or condoms where I can control/ see the evidence. Might be different in a very committed relationship but in anything else, no I would not rely on this.