I hate that old saying "Sticks and stones will break your bones but words will never hurt me". It is bullshit. Bones heal, but words cut you inside. Words stay with you forever. They become that little voice inside your head that undermines every single thing you do. They become that seed of doubt that makes you scared of being a failure, that makes you see everything you do through a dirty lens. The wrong words are like parasites, burrowing their way into your brain and leaching your life of confidence, joy, esteem, laughter, sense of self.
The idea that insults, slurs, and more are not painful or not worth noticing has to do with our society's idea that emotions are worthless. That emotions exist on a binary scale with rationality and that one who experiences one cannot participate in the other. Emotions are not irrational. They exist for a reason. They let you know what your boundaries are. My boundaries might not be yours but that doesn't make them any less valid. If I say that doing this thing is something I am willing to unfriend for, you DO NOT FUCKING ARGUE WITH THAT. If you care to be my friend you listen to it, and if not then leave me the fuck alone. Or better yet, do us both a favour and unfriend me.
Emotions are a “sixth sense”. Not in the colloquial sense having to do with some sort of predictive power, but rather like touch, smell, feel, they are a way that we navigate and experience the world. Without emotion we lose a way we relate to the world and it is as much a disability as losing one’s sense of hearing or sight.
Words do not have just the power that I give to them. Words have power all on their own. They do not exist in a vacuum. If someone calls me fat, yes in that one instance I can choose to decide not to be upset, but that isn't going to change the fact that I live in the world where people can treat me differently and badly because of that word. It doesn't stop becoming a word that can be applied to me just because I choose not to be upset. If you grew up being told that gay people are evil, sinful, going to hell. If you live in a society that feels like they can refuse you your rights because you are gay, that gives the word "F*ggot" power regardless whether or not you choose to be offended by that word.
Words have a history that is not irrelevant. Being called a "r*tard" carries with it every single punch, every single instance of being discriminated against for having a mental illness. It carries with it a memory of every single person that has been called a retard. Every child that was killed for being autistic or being sick in some way. It may be just one time thing or it may something you are called every single day. It doesn't matter. Those words will hurt, and they will stay with you.
The power of words is not just negative however. Words can also do great good. Those familiar with the anti-communist movement Solidarnosc know that words played an important role. One of the main things they did was read all the literature that was banned by the Soviet government. And that’s the point. If ever you doubt the power of words, all one needs to do is look at the fact that all of the most authoritative and corrupt powers are so afraid of words, that they spend countless hours and resources on censorship. Words matter.