To her, that was a hugely significant factor. For whatever reason. I have to say that although I can't see myself ever being in a similar position, if I was, it would be a big deal to me too.
If you have a law of 'rape by deception', which Israel does (and in that article it mentions the law being applied previously in a situation that had nothing to do with race/religion) then you have to have a court that decides its application. The court, who are in full possession of the facts (and you and I are not) have decided that this lie is significant enough to warrant a conviction for rape by deception.
To Darlok, you said yourself you can see some situations in which this law would be valid. In your example of the make-up and padded bra, you would be fully entitiled to take your complaint to the police. The police/court system would then decide if your claim is valid under the law of the country. In this particular case, the court, having seen the evidence and knowing the exact details of the law (again, you and I do not) have decided that the law has been broken.