The speaker is a propagandist looking back on what he has done, and the tone is bitter and ashamed. "I bled ink for this war" makes writing feel like a physical sacrifice, as if words were wounds. Yet the next line shows how others saw him: people watched him "sing and dance," as though his work were entertainment, a cheerful performance. The gap between his private cost and his public image is sharp.
The middle lines, "out of key out of night," suggest something off-tune and hidden, work done in darkness that still looked bright from outside. "The fruit of my endeavors" sounds proud, but it is left hanging, and the reader senses the fruit is rotten.
The ending is the cruelest part. The slogans, "for all for God for the least," sound noble, then collapse into "wrong king." All those grand causes served the wrong side. The mood is hollow and regretful, with a sense that persuasion can lend beautiful words to an ugly purpose.