State police said it is up to each individual community to decide whether to allow sex offenders who have completed their sentences to serve in an office at the local level.

So apparently this Pennsylvania law barring convicted criminals from holding office only provides protection for citizens at the state-level:

§ 7. Ineligibility by criminal convictions.

No person hereafter convicted of embezzlement of public moneys, bribery, perjury or other infamous crime, shall be eligible to the General Assembly, or capable of holding any office of trust or profit in this Commonwealth [state.] Source