The US constitutution sucks if discrimination on the grounds of sexual preference is not unconstitutional.
From the ACLU
Q.Does the U.S. Constitution protect transgender people from discrimination?
A.
Although the Supreme Court has never considered this question, we think the answer is yes. It’s important to remember, however, that constitutional protections only cover discrimination or mistreatment by the government, not by private businesses or individuals.
A few federal courts have ruled that the Constitution’s guarantee of equal protection under the law bars the government from discriminating against people based on their transgender status or gender transition. For example, a federal appeals court in 2011 ruled in favor of a transgender woman whose boss fired her from her state government job because he was uncomfortable with her gender transition. The court ruled that “discrimination against a transgender individual because of her gender nonconformity is sex discrimination, whether it’s described as being on the basis of sex or gender.” However, how courts view constitutional equality protections for transgender people is an area of the law that’s still evolving.
At the ACLU, we believe that the First Amendment, which bars the government from censoring speech or expression, should also protect individuals’ right to wear clothes or groom themselves in ways that express their personal sense of gender. There aren’t a lot of court decisions on this yet, but we hope eventually to see courts rule that gender expression is protected by the First Amendment. We also believe that the rights to “liberty,” “privacy,” and “autonomy” courts have found to be protected under the Due Process Clause of the U.S. Constitution should extend to transgender people’s ability to make decisions about self-expression, medical care, and more, but there isn’t much law on that issue yet either.