I have yet to see competition group mixed session (kickboxing or bjj) where women could match up to men, even with no or very small weight disparity. Most cases its not even close. Maybe its just the gyms I have trained.

It is very common practise that you go much easier if your sparring partner is smaller than you, no matter if its a teen boy, smaller man or a woman.

Are you completely sure that some of the time this "butthurt" attitude is not because you suddenly changed the intensity of sparring session out of nowhere and might have caused injury risk? Because this has happened to me several times when doing light sparring with girls (and young guys) who have something to prove. Note that I did not get "butthurt" regardles, just noted to be more carefull.

Edit: I wanted to include young guys as well.