That you can find a game in which all romance options work both ways it doesn't mean that it's necessarily a good idea.
Also, that you can find a game with exclusive options doesn't mean that's necessarily a good idea either.
It all dependes how it's written. Difference is with either approach, when all LIs are available for both genders, a lot of more people get to enjoy those romaces. If romances are restricted, fewer people do.