Okay, maybe I am going to have to explain why "conspiratard" is offensive, since some people haven't gotten the memo.
First of all, you've just talked about personal insults' being inappropriate, so throwing one out yourself is perhaps a little hypocritical.
Second, are you unaware that the term "retardation" is no longer used in childhood development circles because so many people were using it as an insult? In my opinion, this served to deprive us of a useful distinction, since "developmental disability" and "developmental delay" both cover a lot of territory other than what is covered under "retardation." My son has a developmental delay--two of them, since he has a social delay and had a speech delay that he seems to have outgrown--but is definitely not intellectually delayed, since he's already reading, writing, and doing math.
Third, let's take my friend's son, Arden. Arden has Down syndrome. He was born with all sorts of problems that aren't his fault. We can talk all we want to about whether someone with his brain issues should be considered stupid, but the fact remains that, if Arden can't understand an average--and I don't know the extent of his mental issues--that's a perfectly understandable state of affairs on his part. We don't expect more of him, because there is legitimately something wrong with his brain.
Should I go on? Don't use that word. Don't use any variant of that word. It's ableist and it's offensive and we're better than that.