How should one deal with religious texts that raise doubts about the Sunnah, and should they be avoided if they cause some people to disbelieve?

The Prophet, peace and blessings be upon him, commanded the killing of the black, purebred dog because it is a devil, meaning it is wicked, harmful, and vicious. It is the most harmful and rabid of dogs, the quickest to contract rabies, and the least beneficial, even though Islamic law permits keeping dogs for permissible benefits. Scholars have differed regarding the command to kill the purebred black dog. Some said that the command to kill it is abrogated, so no black or other dog should be killed unless it is rabid and harmful.