You used them as insults, while other people reading about politics, history, and medicine used them as descriptions of individuals either currently or historically. And yet I doubt many medical professionals have trouble not calling people "retard" when upset. Because there's a difference between saying the word and "using" the word to describe how you feel about something.

Repeatedly using the word to express your emotions desensitizes you to the context of the word other than your emotions. Repeatedly using the word as recitation or description might desensitize you to the shock feeling of hearing the word, but I doubt it makes you suddenly express yourself with the word.

The connection to your emotional state is why you categorize those words as catch-all for expressing that type of emotion. This is "bad" where any synonym for bad works, and by repetition you accept "gay" as a synonym.

It's not as simple as "repeatedly using the bad words means I'll use them against people and it'll be bad". "Gay" can also become a synonym for other emotional expressions, contradicting the "bad" association. Pride and label reclamation stuff. Similar has happened with the black community over racial labels.

I can say many slurs without cringing or feeling shock, but that doesn't mean I have any desire to use them, nor do I even think of them when upset. Also, importantly, I can judge when someone will be uncomfortable just hearing the word, and use tact. It's not the word, it's the person, and being compassionate means giving a little. Understanding how best to work with someone without forcing them out of their comfort zone is a good trait to learn.