Than blacks. I agree with Andrew Sullivan. Let us remember that when we are dealing with analogies we can always distinguish in some way or another between what we are comparing; that's why we call them analogies, not duplicates. And although there certainly are similarities between blacks and gays, comparing the two in the context of a pro-gay argument often can be rhetorically ineffective. What blacks have been through in America is so unique that they can meaningfully distinguish themselves from any group that tries to make a comparison.
A few points:
Simply making an argument for sexual orientation "civil rights" anti-discrimination protection, does not, by itself equate with comparing blacks to gays because "race" is not the only category to receive such protection. If we lived in a world where race and only race were a civil rights category, then that criticism would be apt. But that's not the world we live in. Instead it's not only race that is protected, but also color, ethnicity, gender, pregnancy, religion, age and disability, at the federal level, and many more categories at the state and local levels.
The relevant question is, as Richard Posner puts it,
[G]iven Title VII and cognate laws, is there any reason to exclude homosexuals from a protected category that already includes not only racial, religious, and ethnic groups but also women, the physically and mentally handicapped, all workers aged 40 and older, and in some cases, even young healthy male WASPS? Is there less, or less harmful, or less irrational discrimination against homosexuals than against the members of any of these other groups? The answer is no.
Sex and Reason, p. 323
Also if we are going to say that homosexuals may never analogize their circumstance to blacks in any way, then we must also say that none of these other groups may either. Homosexuals historically may not have been treated as badly as the blacks, but could argue that they've gotten it every bit as bad if not worse than women, the pregnant, the aged, the disabled, and most non-racial ethnic groups which are all protected.
I have also seen it erroneously argued that because gays are not economically impoverished, they are thereby disqualified from any minority status. To repeat, this is an utterly flawed notion. First, whether gays are economically impoverished is a matter of dispute. I tend to disagree with Prof. Badgett's thesis to which I linked. But even if gays are more affluent than straights (which if you've seen the neighborhoods in which gays disproportionately congregate, they appear to be), so too are Jews more affluent and better educated than Gentiles. And a similar point can be made regarding Asians to Caucasians. So do we then conclude that Jews and Asians are thereby forbidden from any bona-fide civil rights protection on the basis of their religion/ethnicity/race?
Ironically, this notion that religious right posits -- that gays aren't real minorities because they aren't economically impoverished -- has strong leftist overtones. It was Mary Francis Berry who once infamously said, "Civil rights laws were not passed to protect the rights of white men and do not apply to them." Therefore "race" cannot mean "white" and "gender" cannot mean male (even though those terms are written in the statutes in such a "blind" manner) because whites and males are economically "privileged."
The conservative/libertarian view on the other hand thinks discrimination should be forbidden regardless of the economic status of the "group" in which a discriminated-against person is a member. If it's wrong to discriminate on the basis of race, then it's wrong to discriminate against whites and Asians, regardless that these "groups" are better off economically than blacks and Hispanics. Ditto with "males" and gender.
And that's because the conservative-libertarian view on this matter tends to be more individualistic as opposed to collectivistic. Sure whites and Asians as groups may be better off. But such discrimination occurs on an individual basis. And many whites and Asians who may be discriminated against are anything but economically privileged. The same thing can be said of gays.