Boy, I'm going to get some flak for this one. For the record, I'm straight.
Arguments supporting the usage of "****," "gay," etc:
A) "Using words such as 'lame,' '********,' and 'insane' are okay, so 'gay' should be okay too."
B) "The law says it's okay, and the law says it's my First Amendment right to say what I want to say."
C) "Words only mean what you mean by them when you say them, in context."
D) "People are being too sensitive."
E) "I know people who are okay with it, so it's okay."
Let's go through each of these arguments.
A) Some people have mentioned this before, but I think it's important to bring this up again. Specifically for gay rights in the American context, which I will assume for the rest of this post (because this is where most of the ridiculous behavior occurs), using "lame" or other words I listed is categorically different. The reason being, those who are lame have an obvious physical impairment (here comes the flak). Those who are ******** have a scientifically provable mental impairment. And those who are depressed, while not having any obvious impairment, are still impaired in their day-to-day functionality as a result of depression. Yet all of these groups have the same rights that straight people do in the United States. Just because you're in a wheelchair doesn't prevent you from getting all of the legal rights you can get from marriage. Just because you suffer from depression doesn't mean people are going to systematically bias against you because you're depressed. If anything those who are lame, ********, or depressed are aided in society, as it should be. No one discriminates against people who use walking sticks.
Unfortunately, the same CANNOT be said for gay people. First of all, gay people, unless also lame or mentally ill, have no physical or mental impairments. In most states, it is still illegal to get married if you're gay. Remember folks, as a citizen of America I can say without a shred of doubt that America is a Christian country. Separation of church and state is a farce. The legal rights afforded to married couples far exceed the legal rights afforded to those in a civil union. This, by itself, indicates a systemic oppression of gay people by not just a majority group, but the entire political system. This is fundamentally unfair but more importantly that gives a warrant to my, and others, claims that gays are an oppressed minority group. If you're suffering from clinical depression, you are in no way oppressed. Your argument does not apply. From this point, we can conclude that using the word "gay" as a negative term becomes oppressive because society oppresses gay people. This is a two-way street. Using "lame" as a negative, again, cannot be categorized in the same way because there is no systemic bias against gay people.
B) Just because something is a law doesn't make it right. Think about copyright law or patent law for a second, and realize that the Republican Study Committee even published a memorandum calling for the complete overhaul of the copyright system. The reason laws change over time, and the reason the Founding Fathers allowed for amendments to the Constitution, is because they realized that no law is universally, forever just. Your First Amendment rights, while "sacred" to the United States, must also be limited by the Supreme Court's movie theater ruling. Obviously this is not the same as using a racial slur, but remember that no right is absolute or universal, and certainly not because the law says so. Also, cross-referencing the argument I made against A), the laws regarding marriage and civil union indicate a systemic social bias.
C) Cross-reference what I said at the end of A), that "gay" is a negative term because there is a systemic bias. Context is fine and dandy, but words cannot be analyzed in a vacuum. The sole purpose of language was and is to codify a set way of communication to ease knowledge transfer. This means that words must be analyzed in a way that takes into account society as a whole and the meaning that society gives to this word. I would wager that most of us would have trouble supporting an argument that "pot" doesn't mean "marijuana." There is no negative connotation there, obviously, but by that association alone you accept society's influence on what you say. Context is important, again, but here even in context using the word "gay" indicates that you support the notion that gay people are synonymous with something you don't want to deal with. And again, using "lame" is not the same because there is no systemic bias against lame people.
D) Anyone's judgment of anyone else is subjective. You can argue that people are being too sensitive, but is it really worth it to continue to hurt those people just because you think they're not "strong enough?" This argument also doesn't give any tangible impacts or really provide real warrants to back up its claim. Words typically hurt more than physical pain, especially in today's more "civil" society. Which is to say, they have more of an effect than you think they do. And this is, like everything else, also a two-way street: if people are being too sensitive, they also shouldn't be positively influenced to do better by words. Let's think about that for a minute. Finally, the sensitivity issue is again tied to the theme of minority oppression: when a group of people is fighting for basic rights in society, you certainly don't help them out by claiming that you have the "right" to say certain words, or that they're just being too sensitive. By perpetuating this illogical system, you harm the minority group's chances of attaining basic rights. Is that also worth it?
E) These people might be lying. These people might have given up already. These people are definitely a small subset of a large group. And while some women might have been okay with not voting, I don't think any woman would look back today and say, "You know, I really think we shouldn't have been given the right to vote. It really didn't do us any good, and anyway we really belong in the kitchen." As Steve Jobs once said, "You can't connect the dots forward." Also, the argument that your gay friends use the word "gay" doesn't hold water because as other people have mentioned minority groups are able to appropriate slurs against them as a coping mechanism. People shouldn't be perpetuating slurs as a result. To put it more relevantly, think about how if you're Jewish you can make Jew jokes, but really no one else can. This is in a similar vein, but much more serious.
tl;dr just don't say it it's not hard to change one or two words in your vocabulary. You're not hurting anyone by changing some words you say, and no your rights are not absolute. Good day.