I haven't played the game The problem is not that she isn't a virgin but bc she a main girl is a prostitute. I would be greatly upset playing a game for hours just to find out the main girl I'm interested in is having sex with other man who wouldn't. There's no way you didn't see this coming, Especially if the side girls are just side characters for her story. it doesn't help that you're crashing out this hard at the players and not understanding why people are upset. I'm gonna skip this one.
Romance with her is easily avoided and you can interact with her as just a friend and still help her get out of that life. She isn't THE main girl, more of a side girl, and the rest of the story and characters outside of her little piece of the story she gets is worth getting into.
Just saying, maybe give it a try. You don't need to romance Chika, and you can still enjoy the story as she's a small percentage of the story that can be avoided(and you can choose to leave her alone or simply help her out as a friend, sex isn't forced.)