Here's the thing. Language evolves. And some members of oppressed groups or minorities are taking advantage of that. "Reclaiming" words means to use them of yourself, in a positive manner, in order to reduce their power.
Some people don't like that. They think it sets up a double standard. It's okay for a black person to use the n word (Which I would cheerfully use in this explanatory context, but I don't want to risk falling foul of Google), but not a white one. It's okay for a lesbian or bisexual woman to use a certain word beginning with d.
But it does reduce the power of the word. If you make a word part of your identity, people can no longer use it to hurt you. It works. When you reclaim a word you take power away from that word and give it to yourself.
Which is why censoring these words is a problem. It really is. When you tell a lesbian or bisexual woman she cannot call herself a "dyke," you take power away from that woman and give it back to the word. You threaten that woman's power over herself, control, and identity. The same for any other "slur" that people have worked hard to reclaim.
It's not a double standard to say people can call themselves by whatever words they wish, no matter how derogatory they may be or have been in the past. It's granting those people power over their own identity.
As a bisexual woman, I am far more offended by this than I could ever be by somebody calling me a dyke as an insult. Far more.
So, if you find yourself saying certain words should never be used: Think. Think about context and who is using them. Because when you say a word can't be used, you give more power to that word, you give power to the people who use that word that way, and you take it away from the people to whom the word actually refers.
Just think about it.