I hate how this is even worthy of a conversation. Someone used a derogatory term on twitter. That's what you're fucking discussing right now. Just think about that for a moment.
The majority of the conversation in this thread is around language, it's power, when and how it is offensive etc. It's a worthwhile conversation that was merely sparked by this tweet. Sometimes a good conversation can have seemingly trivial origins. The OP seems to recognize this in the post. Think about that for a moment.
I don't think the point is to discuss JonTron's post but rather to use it as a springboard to ask the question about the use of "retarded" on Hubski. After all it's a word where reactions range from "Who gives a shit" to "I think it's an outdated term" to "old habits die hard" to "People who use it are assholes". Even if you already have an opinion on the term, it's still helpful to gauge the community, let you step on a toe (Or, hey, now one can link this thread to cover their ass down the road).