Can you see how rtard is perhaps similar to the homophobic f-slur? The word is used as a pejorative with the implication that the group it is most commonly used towards (disabled, gay) is being used as a point of negative comparison. While I think we should be aware that the use of language is incredibly context-rich, we also need to recognise that the words we use have side-effects. Would you feel comfortable if a friend of yours dropped something and said "oh damn, I'm such a <n-word>"?
Speaking of the f-word, I’ve seen it used non pejoratively at the embarcadero farmers’s market. One of the vendors sells them for home decorative purposes along with cattails, lavender, etc.
Being from the UK, I hear it all the time to refer to cigarettes. When I worked in a shop, my colleagues would just walk through the shop and say "just taking a f* break". While it was totally inoffensive, it did make me a bit uncomfortable. Piquing my sjw sensitivities, I guess
Personally I find it disturbing that adults discussing the word feel the need to type things like “f-word” instead of just typing the word fag. You’re talking about a cigarette. It’s a configuration of 3 particular letters. There’s no reason to react to them in that context.
There isn't any relation other than the word being used. It's not something I ever complained about because I understood that it wasn't offensive in any way and is, like I said, just the response I have to hearing that word.
I think there's a public/private divide here. You can use whatever language you want with people you know, because you know how they'll react and that it genuinely won't cause offence. In a public space though, I'd be wary. A black person walking past a group of white kids making racist jokes and using racial slurs is only going to make them feel less comfortable, even if the white kids genuinely mean no harm.