The point is that Huntress is well past being in a state where she'd sleep with someone unless she really wanted it. She wouldn't do it just to feed Hal Jordon's ego.
Besides, as Gail Simone emphasized in that thread on CBR, Zinda and Helena are friends. And saying "well, Helena's had sex with a bunch of people" is justification for her participating in a threesome along with Zinda is kind of problematic.
By that logic, both Hal and Ollie should be having threesomes together with women regularly in canon. But we won't see that throw-away line, because that would mean implying that two of DC's big-name white straight male heroes are not as straight as previously thought.
I may be going out on a limb here, but I do get the feeling that TPTB at DC are a lot more comfortable with female heroes who are gay than male heroes who are gay.
(And let's face it, there's so much more fuel for Hal/Ollie at this point than there is for Zinda/Helena.)