Herc, per Perez, raped Polly. Polly, per Perez, forgave Herc and made sexytimes with him on a Themysciran beach three thousand years later. Polly, per Gail as of a year ago, may or may not have forgiven Herc, but apparently at the very least never made consensual sexytimes with him. Diana's complaint about the movie is the first we've ever heard of Polly not having a romance with Herc.
Fair point about Herc hitting on Cassie, though I didn't really get the impression he was actually serious about that the way his romance with Polly was serious or Mike Schorr's crush on Diana was serious. He kind of just bugs her about it a couple times then moves on with a shrug and a "whatever."