A more thorough explanation:

The government speech doctrine is a legal principle that says the government can express its own opinions without being limited by the First Amendment's Free Speech Clause. This means that the government can say what it wants without having to be neutral or fair to other people's opinions.

For example, in Rust v. Sullivan, the Supreme Court decided that the government could fund family-planning programs and prevent healthcare providers in the program from answering pregnant women's questions about abortion. This is because the government was expressing its own opinion about abortion, and it did not have to be neutral or fair to other opinions.

However, in Legal Services Corp. v. Velazquez, the Supreme Court decided that the government could not prevent lawyers in a program supporting legal representation for indigent parties from helping those parties challenge or amend welfare laws. This is because the government was not expressing its own opinion about welfare laws, but rather providing a service to help people access legal representation.

It is not always clear when the government is expressing its own opinion or restricting others' speech. The government cannot ignore other parts of the Constitution, such as the Establishment Clause, which prohibits the government from promoting or favoring one religion over others.