I am not saying she felt unsafe in the moment. I couldn't know, but I agree she probably didn't. (She may have felt unsafe about speaking to them directly about their behavior, though.)
I am saying that one reason we don't make sexual comments in professional contexts is that it can make people feel unsafe.
I'll stipulate that the woman was pissed off, but in no sense did she feel unsafe. When I search her post for the string 'safe', I find one mention of the dorky dudes' temporary feelings of safety and how that sort of thing leads to genocide. There is another mention of PyCon being safe in a general sense. There is no claim that she ever felt unsafe, and your focus on that adjective is unhelpful.