Is "mongo" the equivalent of English "retard", in terms of being a low-class insult that invokes a visceral reaction among the majority of the population?
I didn't believe that at first; if so, why didn't anyone ever put it in Wikipedia? English has "retard" (in the pejorative sense):
https://en.wikipedia.org/wiki/Retard#Other_uses
And why doesn't it show up in a top-result Spanish dictionary?
http://www.spanishdict.com/translate/mongo
If it's merely an insult with numerous other meanings, I don't think it's comparable.
But let's assume it is equivalent to "retard". In that case, I would agree that it shouldn't be used as a name. But you have to pick your battles: all words will have that trait in some language. For my part, I would consider the Spanish-speaking market big enough not to expect them to buy [the equivalent of] RetardDB. So I agree there.
Edit: I agree with the sibling commenter networked's points.