Permit me to shed one big crocodile tear for Haynes Johnson and Judy Mann, who are crying the blues over recent actions against pornography and other objectionable materials.

In his July 23 column, "Modern-Day Book Banning," Mr. Johnson lamented the fact that the Wal-Mart chain has removed rock-oriented publications and condemns the fundamentalists for "writing a new chapter in the shameful story of book-banning." Mr. Johnson's comment on the textbook trial in Church Hill, Tenn., is to ban the Bible because it recounts immoral acts.

Writing on the same day, Judy Mann, in her "Censorship's Nose in the Tent" column, similarly agonizes over the disappearance of rock magazines from Wal-Mart stores and hits hard at the Attorney General's Commission on Pornography for playing a role in the removal of Playboy and Penthouse from thousands of retail outlets.

Mr. Johnson and Mrs. Mann will simply have to learn that Americans have not suddenly become prudish busybodies. Instead, the publishing industry of late has been turning more and more toward smut and other undesirable materials. And the good citizens are not going to tolerate it any longer.

Another lesson for Mr. Johnson and Mrs. Mann is that the real censors in the United States are the book publishers, the book store chains, the educators, the schoolbook selection committees, the librarians and the news media. They are the ones who determine what Americans shall and shall not read through the powerful tool of selectivity.

Judy Mann wrote, "Censors have a way of putting the heat on something fairly obnoxious and then before you know it, everything else is a potential target." That is an interesting thought indeed. Perhaps Mr. Johnson and Mrs. Mann should worry less about the decreasing supply of pornography and direct their thoughts more to whether the management of The Post might consider their columns "obnoxious" and censor them out of the paper.