At one point, the WTS semi-publicly stated that sex offenders could not hold positions of authority/responsibility in JW congregations.
Recently, however, that restriction has been loosened to allow "former" offenders to serve if their past misdeeds are on the down-low.
This is another big reason they're culpable for the abuse to children by elders/MS or anyone with priveledges in the congregation that's a known pedophile. Right up until I educated myself on their real policies in the secret elder's book, I completely believed that known child molesters weren't allowed to have priveledges. I would be shocked if this wasn't the belief that most in the congregation have (as you say, it was publicly stated as such not too long ago). This means that, having secretly changed the rule, when they so much as have a pedophile carry the microphones on one sunday, it is viewed by the R/F as an endorsement for him to babysit your kids.