I'm really confused about the how the creators of that website intended for the question to help in deciding whether a user should date a certain individual.

It's up to the users: you have to both provide your own answer and decide which answers you would consider acceptable in a potential match (and specify how much of a big deal would it be for a potential match to pick a different answer). If you want to provide your answer but don't want to discriminate potential matches based on their answers, you can mark all possible answers as acceptable or equivalently mark the question as irrelevant. (And many of the questions are written by users of the site, rather than by its creators; I don't remember whether the one about nuclear war is.)

The matching algorithm is described here. (Its unBayesianity makes me cringe -- the rarer a particular answer to a particular question is, the larger the effect of someone picking that answer ought to be -- but still.)