Your simplistic view of the law/lawyers is laughable.
Someone accused of committing a crime is entitled to a defense by a competent lawyer. A Lawyer is obligated to zealously defend their client in one of two ways. 1) Raise reasonable doubt as to their clients guilt or innocence by offering an alternate theory of the crime. 2)Offer proof that their client is not responsible for his actions/his actions are justified.
A “Frum Yid” can do these things without agreeing with the things his client has allegedly done. edited for unnecessary slander
edited again for unnecessary remarks which may or may not be true, but will unnecessarily sidetrack the discussion.