Neither party has to be lying. She might honestly believe she was treated in a specific way because of her sex, while others may have treated her in a specific way because of, for instance, her competence. Both may be 100% honest in their assessment of the relationship, yet be completely at odds.
The workplace absolutely sounded unprofessional, which often means the entire gradient of behaviour from welcoming to hostile (versus the normal corporate realm of gray areas in between). Indeed, unprofessional workplaces are generally celebrated in the tech community, often for good reason.