Because both an employee and employer can make whatever claims their want and claims from both sides should be viewed as suspect absent evidence and witnesses. This becomes a gender issue when other people support that claim. Until evidence or a credible witness corroborate the claims, it's a disagreement between an employee and employer. We have zero evidence to support anything more than that at this point. To claim otherwise respects neither science nor due process.
My point is that the allegations are gender-based in nature, which makes this a gender issue by definition.
This did not become a gender issue when "other people support[ed] that claim." This became a gender issue the moment Julie claimed she was harassed because she was a woman. Whether her claims are invalidated or not doesn't change the gender-based nature of her claims--it would simply mean that her claims (which are still gender-based!) are not supported by the evidence.