Ironic. According to the wiki, she loathes men with passion. What changes her, I wonder?
English wiki (on fandom.com) is outdated. Her old JP character bio (circa 2018?) had that snippet, but it has since been removed some time before she was implemented in-game.
Likely because:
The player character Trainer can be female or male, and it didn't make sense for a "fervent man-hater" Air Groove to have similar interactions with both. Recording/writing separate lines isn't feasible either.
The way it was written (caused by a traumatic incident in a race) may also raise some logical inconsistencies/unfortunate implications, as all umamusume are female regardless of their real-life counterparts.
It might possibly overshadow Mejiro Dober's trait, who has "shy with men" listed. (That one is probably easier to implement and doesn't cause jarring inconsistencies in how she reacts with female and male trainers).
They change things around for quite a few umamusume between initial conceptualization and later implementation (or soon-to-be teased implementation). This include things like removing Air Shakur's "LEET hacker" trait and turning Manhattan Cafeinto a pettanko.
TL;DR: "Man-hater" Air Groove has been retconned out.