Because one man didn't sign off on it...it was still approved by federal agencies (chief of staff, director of CIA) with intent to completion upon executive approval... the executive that refused to sign it was later assasinated the following year.

It's crazy people act like it's a preposterous idea the government could or would.do something like that when they have already ADMITTED to the Muskogee airman experiments, project MK Ultra, operation Bongo II, the gulf Tonkin incident, and the Snowden revelations....and then planned operation northwoods.