I have not read his book.  None of the reviews I've read, positive or negative, has claimed that Fr. Martin has exhorted us to reject Church teaching.  The negative ones fault him for not repeating it.  I have not seen anything which indicates Fr. Martin has argued to accept gay conduct as acceptable.  Some have claimed that Fr. Martin has implied acceptance because he has not specifically condemned such conduct.  I don't buy that claim.  Even if true, it is not an exhortation.  Can you cite a source for your claim?  How has Fr. Martin not held "true to the one true faith?"