This wasn’t the way Christian Bales planned to leave high school.

Mr. Bales, an 18-year-old with a passion for conservation science, worked hard at Holy Cross, a Catholic school in Covington, Ky., earning the honor of valedictorian. He looked forward to delivering a commencement speech at the graduation on Friday.

Then something happened that left him “kind of shocked,” he said.

The principal and other officials told him on Friday that the Diocese of Covington had deemed his speech too angry and confrontational, Mr. Bales said.

“I did not think the speech was polarizing at all,” he said. He was told that it was political and personal and that there was no time to revise it.

Mr. Bales is gay and describes himself as gender nonconforming. His speech, which can be read in full here, makes no mention of either.