They may be an expert identifying and managing crabs, but "the wisdom of this world is foolishness with God" (1 Corinthians 3:19). "And all that have not fins and scales in the seas, and in the rivers, of all that move in the waters, and of any living thing which [is] in the waters, they [shall be] an abomination unto you" (Leviticus 11:10). And no, Jesus did not clean it up not was Peter's vision a command to eat such creatures. A crab is the same physical crab since the beginning of time. Jesus did not change their digestive systems. These creatures are not spiritually unclean. They are physically unclean. They contain poisons that are actually harmful to human beings.