good in a case where following the law would do grave injustice, bad because of local prejuidice would let perpetrators walk.
If society believes that something is "wrong" they will convict someone who does it. That's why defense attorneys in rape cases still demonize the complainant's sex life. Since society thinks promiscuity is "wrong" they will vote against her.

But IMO no law should ever force a jury to convict a defendant whom they don't think has done anything "wrong." This is related to my opinion that laws should set maximum panalties for crimes, never minimums.