Obviously as a private group DEF CON’s organizers have every right to contract with whatever companies they want to. In the same way, obviously the private individuals paying DEF CON’s organizers have every right to criticize them when they treat their contractors so poorly. However , I think it’s short-sighted and self-defeating to suggest that they shouldn’t ALSO have the right to criticize their choice of companies they work with when it impacts the quality of what they’re paying for.
This is not a sexist, anti-POC, or anti-trans criticism. Deciding on contractors for the reasons they claimed they did would be illegal in the public sector under France’s anti-discrimination laws, under Germany’s Grundgesetz, under Japan’s GPA, under the UK’s Equality Act in many cases, etc.