The reason I'm so confident is that I, and everyone I know, personally welcome and would hire and help competent women and bright-but-just-starting-to-ascend-the-learning-curve ones too. I've coached a female colleague in preparation for a successful job talk at Google, for example (same as I'd help any colleague I thought had a shot and asked me).
I've admitted that I don't know the culture in every company and part of the U.S. and do think if we're serious about protecting women from unfair discrimination we need to screen out whoever, due to cultural differences, cannot be professional in hiring and working with women). Professionalism is a pretty low bar and I'd expect even H1Bs from more gender-traditional cultures to be able to pass it, no matter their private preferences+beliefs.
I've admitted that I don't know the culture in every company and part of the U.S. and do think if we're serious about protecting women from unfair discrimination we need to screen out whoever, due to cultural differences, cannot be professional in hiring and working with women). Professionalism is a pretty low bar and I'd expect even H1Bs from more gender-traditional cultures to be able to pass it, no matter their private preferences+beliefs.