Then there is the precedent that this verdict sets for blaming the carriers of illness. If a guy can be convicted by the courts for passing on HIV, why could he not be convicted for passing on other infections - chlamydia, for example. It is unlikely that Kelly failed to disclose his HIV status because he felt he would be immune from prosecution. All sexed up, with a willing and ready partner, his mind was probably on rather more immediate concerns. Think about how difficult it is for some couples to step back from passion to consider contraception.
Sex is hot - cool, rational calculation tends to be thrown aside with the clothes.
This judgement is unlikely to protect anybody's health - but it succeeds in conferring victim status on sexually active women, and pushing back the barriers of privacy by extending areas on which the court can judge. The more the law courts have to say about the rights and wrongs of sexual negotiations, the more uncomfortable we should feel.