A commenter on the "Suppression of Homosexuality-Related Speech" thread writes:
Is the ACLU defending students rights to wear shirts which read "Be happy, not gay"?
What if a student wanted to wear a shirt which stated "Be Ashamed, Our School Embraced What God Has Condemned"?
What about if a wedding photographer decides not to photograph a same-sex "marriage" ceremony?
What about if a dating service decides not to offer same-sex dating services?
What if a religious organization refuses to rent its property for same-sex "marriage" ceremonies?
What if businesses in Colorado wish to put up posters that list Biblical prohibitions against homosexuality?
Where is the ACLU on these cases? Or do First Amendment rights only flow in one direction?
Naturally, different organizations have different views of the scope of constitutional rights. Some might, for instance, see refusals to rent property as covered by the First Amendment or some other provisions; others might not. One can certainly fault groups for taking a view of constitutional rights that you think is mistaken — I've certainly faulted the ACLU in the past on these grounds — but it seems to me that one needs to do so with some explanation for why your view is right and theirs is wrong, rather than just based on an assumption that this is so. (One should also recognize that different ACLU chapters run their own show in large measure, and different ACLU officials have different views. For instance, ACLU President Nadine Strossen has prominently condemned some of the excesses of workplace harassment law as applied to speech, and might well opt to support businesses' First Amendment rights to put up posters with anti-gay speech; but the ACLU of Colorado might well take a different view.)
But beyond that, it helps to do some Googling: A Google search for aclu "be happy not gay" reveals this item from the Alliance Defense Web site (among many others):
ACLU opposes school in "Be Happy Not Gay" T-Shirt case
The AP reports on The Rockford Register Star (2.19.2008): "The American Civil Liberties Union has joined a Naperville high school student in her fight to wear a T-shirt that expresses opposition to homosexuality on moral grounds."
This is an ADF suit. View ADF press releases and documents here.
Again, I'm happy to agree that the ACLU gets things wrong by my lights in many cases. But we should be careful before making casual, unresearched assumptions about what the ACLU's position (or other groups' position) must be.
UPDATE: A commenter argues that the ACLU of Illinois' support for the "Be Happy, Not Gay" student was inadequate; but while the ACLU brief was termed a brief in support of neither side, the Alliance Defense Fund knew what it was talking about. In particular, as the ACLU brief makes clear, the ACLU took the view that the school harassment policy supposedly covered the T-shirt was unconstitutionally overbroad (p. 22), and that the students' plan of wearing the "Be Happy, Not Gay" shirt the day after the pro-gay-rights Day of Silence would not constitute harassment and thus would be constitutionally protected (pp. 20-21).
The ACLU opposed the student's request for a broader injunction allowing him to engage in unspecified speech opposed to homosexuality. But as to wearing the "Be Happy, Not Gay" shirt (which is what the commenter initially mentioned) in response to the Day of Silence event, the ACLU was pretty solidly in favor of the student.