Is HR the department that post jobs and requirements in your company? Because at mine, HR is involved during recruitment, but they sure don't fill job posting or look at CV, that's just isn't their job. They are mostly involved if the company wants to transfer your contract from contractor to permanent employee.

And if HR is posting on job boards, that's the original mistake. But gender ratio in HR is so irrelevant compared to the questions 'why is HR posting about engineering open positions' I can say quite confidently: that's not a fair question, at all, and smell like some ragebait or culture war shit.