Where are you getting this "mentally challenged"? Show some citations. Show me where the ASVAB scores have been lowered and then I might agree. However, I do agree the social engineering of the services certainly hasn't helped.
"We spend a staggering amount of money on TV commercials and other recruiting efforts."
DOD has always spent a lot of money on recruiting since the volunteer service. I was a Recruiter in 1986. The new one to me is seeing the Air Force commercials. What's that about? They used to be the first service potential recruits would talk to in a multi-service recruiting office. Because of not meeting very high AF standards, the potentials would then go to the Army cubicle and then the Marines.
Navy was last because so many afraid of the water, with no where to go if getting torpedoed. The youngsters thought they were invulnerable against bullets or duck or hide from them, not so when the ship is going down. Again that was 1986. Recruiting standards ARE probably lower.
I didn't write the article.
But that said, here's a citation...Army lifting ban on bipolar, self-mutilating recruits 'a red flag'