It is often the case that a "good" word is used, and then the derogatory secondary meanings grow.

Years ago special needs was a fairly safe term, yet now "speshul" definitely has different tone. I'm sure you know if many other examples (I can think of heaps). I predict that "delayed" will become derogatory.

I think that banning words is literally dumb. I am bit older and went through the Politically Correct putsh. Disclaimer: I'm a lefty.