Matrix Morpheus

And the term 'Retard' was used to define intellectual disability.

Idiot, imbecile(25-50 IQ) and moron (50-69 IQ) were all medical classifications. They became offensive once they began being used by non-professionals. Much the same way any descriptive term will eventually become politically incorrect.

First of all, the word "idiot" can be directly traced back to the ancient Greek word "idiotes" making laymen - non-professionals, uneducated people. The concept of an Intelligence Quotient metric was first proposed in 1912.

Second, the IQ is defined as a normal distribution with mean of 100 and standard deviation of 10. Mathematically, this means that 99.5% of people will have IQ of 70 or higher. Your moron classification of 50-69 would catch hardly anybody - we're talking thousands of people globally. By the time you get down to 50, 40 IQs, there are none, in the world. Never in your career would you come across someone with an IQ of 25 - unless you were a hack who didn't understand his own science; I suspect that was the case in whoever published the result you're citing.

If you do some reading up on early 20th century psychology and Henry H. Goddard you will come across these terms. Moron was a term borrowed from the ancient Greeks as are many terms that have been used through the centuries and up to today. Why is this an argument?

You are correct that the word moron WAS originally coined specifically for clinical purposes, and was dropped when it crept in to common lexicon as a derisive term. But that's not what the original meme said.

I have no doubt that early psychologists also had a clinical use for the word idiot. But that's not what the original meme said.

I do not doubt that Henry Goddard published the guidelines you referred to. But guess what? He was one of the hack scientists I was talking about. Even the man himself admitted that much of his work was scientifically flawed later in life. So again, referring back to the original meme: there's no way that "idiot" could have been coined just to describe an IQ that literally never happens when it's been in colloquial use in multiple languages for thousands of years.

To answer your question: I don't know!

Good enough answer for me :)
And I won't deny Goddard was a hack, and he, his work and those terms were actually used to illustrate bad psychology when I had it many years ago. I agree the meme would have been more correct to say "entered the English language as". I tend to look more at the intent than the execution which sometimes leads me into discussions where initially it appears the sides oppose, but actually agree. Anyway, fun discussion and I got to brush up on some old lessons. Thanks!

Anytime, buddy! Looking back, you're right - the syntax of the wording makes the overall meaning ambiguous.