I don't think there is a need to "respectfully disagree" to a disrespectful comment. Just like there are terrible dev teams there are terrible HR departments, and this sounds like one of them.
But as you mention, if developers were to handle everything related to hiring, firing, sick reports, vacation, benefits, contracts, compliance etc. that HR does, I doubt there would be any profit.
But as you mention, if developers were to handle everything related to hiring, firing, sick reports, vacation, benefits, contracts, compliance etc. that HR does, I doubt there would be any profit.