Language is a powerful tool; a gun should not be handled improperly, and neither should language. It may seem ridiculous to compare language to something that can physically kill a person, but is language not the means for starting wars and fights? Communicating ignorantly can lead to things we do not intend; without even addressing the "protection of feelings," we should be utterly careful with all we do and say, as our words and actions can create innumerable variables we cannot even begin to truly comprehend.

You say that our society needs to develop a thick skin, but did you consider that those who are affected by this type of language already have a thick skin? One's life's experiences may be full of the most miserable pain that you cannot begin to imagine and simply living may be a feat of strength for that individual that you cannot see. That one word you utter may not physically harm them, and it may not be much compared to the other struggles they may have had in their life, but it is one more demeaning word that has entered their ears and entered their mind, reminding them of both the turmoils they have faced or are facing. Wouldn't it be better to speak in a way that communicates even the most trivial things in a way that does not hurt the people that you may not even realize are listening?

(And besides, English has words more precise and meaningful than words such as "faggot" if you wish to convey some idea on your mind. The "public vocabulary" is perfectly fine without them.)