Although it’s a very good thing to point people at wrong and/or offensive choices of saying things, it is whole different thing to call it sexism and call for a boycott of the whole project the ‘offender’ participates in. I have not watched the video of Mark Shuttleworth uttering the controversial phrase, but I did read a few (semi-)transcripts and reports of people that did watch it.
What I’ve read about it didn’t sound like sexism at all. Some people definitely overreacted; boycotting is way over the top, asking for an apology is misplaced as well. I’ve always been told at school and by the media that sexism is “prejudice and discrimination based on sex” — source of the English description: Merriam-Webster. What Mark Shuttleworth said may have been wrong and offending to some, but it was not sexism. It would have been if he’d said: “I think that all women are unsuitable for FOSS.” That would have been gross sexism. But this was not. He just used bad wording.
Pointing people at the use of wrong and offensive phrases is an important task. If you want to get emancipation — I’m hesitant to use the word feminism since it has got such a negative sound here these days — to succeed you need to make sure the used language doesn’t exclude anyone. However, when overreacting you scare people away as well, and it’s at least bad for your image. How gladly do you think developers would like to participate if every tiny breach of gender neutrality and equal valuation, even if by accident, will be mercilessly punished?
Please do, really do, keep alerting us whenever we make a mistake and accidentally — or willingly as well — offend women, men, youngsters, elderly, programmers and non-programmers. It is helpful. However, please be reasonably. Without reason you won’t get far.