Yeah, I know that, but it's not uncommon for a charge to be trumped up in order to persuade a defendant to settle for a lesser charge instead of fight it in court. I'm not saying they're completely innocent here, but the article doesn't mention any convicted rapists or murders, which would be much more pertinent to the point of the article.
It even says "500 accused of a sex crime". That's pretty open-ended and shouldn't be taken as 500 rapists. I wouldn't even be sure that the article is using the "sex crime" legal definition, or if they just made up their own definition.