Upon reading the poem for the first time, I believe the tone of the text is desperate. There are two ways I have come to that conclusion.
1: Process of elimination: You know the author is not delighted because he is saying all these things about America that express how he feels about it. Just by looking at the title you can infer that the author wants America to be the place that it once was. You can also cancel out hopeful because he is not hopeful that America will ever be the same. For Example, when he says, "(There's never been equality for me, Nor freedom in this 'Homeland of the free.)", he is talking about the fact that America was never about equality and freedom, especially not for him, or people of his race. (Keep in mind he is African American.) Canceling those out leaves you with desperate and confused. I would take out confused because he is confident with that he believes. He does not question himself and what he says; Such as when he talks about freedom and equality. He never questions if there ever was once freedom or if there ever is. He says that he believes there will be in the future. In the end I chose desperate because he is talking about making this 'horrid' place a better one and a place where the mistakes of the past are not repeated.
2: The second way is by analyzing the poem. The whole time the author talks about the wretchedness that had occurred in the past or was occurring while he was writing this poem. He states, "The r*pe and rot of graft, and stealth, and lies." Of course, all of these are bad and not wanted. He is desperate to make a change and make America a better place or "make America again!"
Sorry for the long answer, but I hope this helped. Its beautiful poem and I'm glad I got across this question so I could get a chance to read it myself. Please update me so I could know if I was right! Haha! Good luck! ♥