On the face of it, this looks like one of the cases where the ACLU should be commended for defending the free speech rights of people with whom it does not necessarily agree: Andy McDonel wants to fly the Gadsden ("Don't Tread on Me") flag from the roof of his house in Laveen, Arizona, and the state chapter of the ACLU says he is entitled to do so. The problem: McDonel is not fighting an intrusive local ordinance or boneheaded state law; he is fighting the rules of his own homeowners' association, rules that he accepted when he bought his house. As the lawyer for the Avalon Village Community Association notes, "anyone considering residing in a community association should carefully review the association's governing documents beforehand to ensure that the community is a good fit for them."
In response to disputes like this one, the Arizona legislature passed a law overriding homeowners' associations that ban outdoor flag displays. Although the statute mentions only the American flag, the state flag, Indian nation flags, and flags of the armed services, the ACLU argues that "the Gadsden flag meets the spirit of the law." In other words, the ACLU is defending McDonel's freedom of speech by supporting state interference with the contract and property rights of his neighbors, who have chosen to live in a development with picky aesthetic rules and presumably derive some benefit from that arrangement.
There are similar problems with claims that the First Amendment or similar provisions in state constitutions protect the right to say whatever you want in private shopping malls, an issue I discuss here and here. Likewise with the assertion that the Second Amendment guarantees the right to carry guns on other people's property.