Retard may not be in there as a swear word. It could be a comment regarding a "delay". [1]
[1] :to delay or impede the development or progress of : to slow up especially by preventing or hindering advance or accomplishment
In Germany we have "Retard-Tabletten" (Tabletten = pills), which are not intended to stop (or accelerate) cognitive decline, but release the active ingredients with a delay.
It's baffling anybody would think otherwise. Reddit auto-censorship (and such auto censorship elsewhere) has a lot to answer for.
Indeed. Most of the matches for "retard" have the meaning of "delay":