The Pulitzer Prize winner -- known for scripts such as "Wag the Dog," "Glengarry Glen Ross" and others -- took a firm stance against DEI initiatives during the Los Angeles Times book festival on Sunday ... where he appeared to promote his memoir.

David made it clear he's unimpressed with Tinseltown's attempts at fostering diversity, equity and inclusion ... slamming such efforts as "garbage." He added ... "The [film industry] has little business improving everybody’s racial understanding as does the fire department."

DM suggested Hollywood has gone too far in an effort to support often marginalized groups, especially following the 2023 writers' strike. David suggested individualism would suffer in the long run.

Of course, this wasn't the only shocking stance shared Sunday ... as David also came for the criticism against nepo babies. Remember, his daughter, Zosia Mamet, starred in HBO's "Girls" for 6 seasons -- skyrocketing her to fame.

David doesn't believe his fame played a factor in his children's success ... defending his kids earned it by merit. He noted ... "Nobody ever gave my kids a job because of who they were related to."

Lots of strong opinions here from David ... and it sounds like some of it was well-received. You can tell the moderator was trying to give him a chance to correct himself and say something PC ... but the dude steered clear and stuck to his points, especially on diversity.