There's no black and white answer and the poem is certainly open to interpretation. What is certain is that the speaker (the Patriot) is someone who was once beloved and welcomed by the public, but has since become hated and reviled.
Many interpret the poem to be talking about a soldier. He speaks of his return from war a year ago when he was celebrated as a hero and welcomed by everyone with open arms. However in the present, they are violent toward him.
Some believe that the "Patriot" is a Jesus character and that the poem depicts his last days; when he was first welcomed to and celebrated in Jersualem days before his crucifixion. Just as the with the Patriot, the public quickly changed their opinion and went from celebrating them to persecuting and acting violently toward them.