'an open advocate' is a correct and usable phrase in written English.
It typically refers to someone who publicly and openly speaks up in favor of or against a particular subject or cause. For example: "John has always been an open advocate for workers' rights, so it's no surprise to see him speaking up at the town hall meeting."
Coke was no objective historian but an open advocate of the common law.
Ho, a 19-year-old freshman, is an open advocate for the former secretary of state, but admitted that being a Clinton supporter can be difficult.
Barghouti has been held in Israeli prison since 2002, for murder and terror crimes, but before that he was an open advocate for the 1993 Oslo Accords.
The fact that a scientist of his caliber is an open advocate for nootropics lends to their credibility.
Carey, married to actor Nick Cannon and expecting a child in the spring, is an open advocate of gay marriage rights.
Today she is an open advocate for gay rights and is using her memoir to publicly draw attention to a way of life that hopefully will become a historical story.
Instead of lockout laws other groups such as Keep Sydney Open advocate "a holistic and lateral approach" to preventing alcohol-related violence.
The UK is losing around £1.5bn annually because of its failure to embrace open access publishing, according to an open access advocate.
These include the work of his friend and adviser István Csurka, an open antisemite, advocate of the Jewish conspiracy theory, and president of the Hungarian Justice and Life party.
If they do not, it is common for Alyona to become confrontational – as she did with guest Jake Brewer, an open government advocate, when he told her audience that Barack Obama runs a transparent presidency.
Michael King, an open space advocate whose group, Phillipsburg Riverview Organization, has been trying to stop the project, said that the city of Phillipsburg, just north of Pohatcong, is burdened with scores of vacant buildings.
