Its a breed gone bad. Any singular pit can be raised to be gentle and friendly; but its the "bent" of the breed, and its natural inclinations.
These DOP's are not unlike the ROP. Humans that have been raised over 7 centuries to kill others. Many ROP'ers have been raised to be tolerant of others and friendly to infidels. But, as the DOPs, its the bent of their breed - to slice off the heads of others.
Islam is genetic? That's about the most ridiculous thing I've heard.