Dr. Phil is uncovering a terrifying Jeffrey Dahmer tale -- 2 men raped, beaten and tortured by him who say the Dahmer in the Netflix series is not the "cold-blooded killer" they encountered.

Dr. Phil joined us Tuesday on "TMZ Live" ... telling us about several interviews he conducted for his 3-day series about Dahmer, his victims and their loved ones. He says many family members were hurt by Netflix's decision to create the show ... which has forced them to open up old wounds.

Case in point, the 2 men who knew Dahmer while he was in the army, and whose stories were not part of the 'Monster' series on Netflix.

Phil says they described their encounters ... which included getting drugged, and in one case, raped -- but according to them the military swept the attacks under the rug.

He's also featuring an interview with Dahmer's father, Lionel, where they dig into the killer's formative years ... and Phil says Lionel admitted missing several red flags.

As we've reported, the popularity of the Netflix series prompted ill-timed costume choices, pieces of Dahmer's ensemble going up for auction, and even a pizza special in "honor" of the mass murderer.

There's also been tremendous backlash, and Phil says his aim is to provide a platform for those most upset by Dahmer's macabre popularity.