This is venturing into a lot of stuff I don't know much about (and don't really have the brainspan or time to really understand), but I did want to toss in my two cents...
First off, yes, after reading some of these reports about how people treat different genders in science fields, I agree there's an issue. Someone talked briefly about a study here with identical resumes given with only the name changed (sadly, skimming through the thread a second time, I couldn't find it to give proper credit) and the female name was far less recommended than the male name. A few other people mentioned how women are generally passed over for awards. These are all issues that we should work on fixing.
The microaggression sexism bit, though? I don't think that's a very large issue, or at least not as large as some people are making it out to be. I could be entirely wrong on this, of course, and like I said it's not something I've really spent much time looking into. Regardless, I don't think the fact that he wears a shirt like this is any kind of significant barrier to entry, nor do I think it's a sign that there's a much larger problem, at least not by itself.
I also don't think that a smaller representation of women in these fields compared to men is an issue. As Consortium pointed out, the rate of advancement within the field is pretty comparable between men and women, so whatever's causing less women to get in, it has more to do with something that happens before they enter the field. Personally, I think a large portion of that can be put on genetics and brain chemistry, though I admit that gender roles in society also plays a large factor.
As for Cycle's idea of firing him... no. Flat out, no. If he were hired as a PR guy, where that was his main job? Yeah, I could see causing a mess like this would get you fired. "PR guy" is not Matt Taylor's job, however, just a brief role he took on for an interview. Should he have worn something more professional? Yeah, definitely. Should the fact that he didn't put his science career in jeopardy? No, and anyone that thinks otherwise needs to take a long look at their priorities.