Writing on Facebook late Tuesday, Mr. Goodyear explained that he had decided to withdraw as a result of the “social media frenzy” surrounding the engagement.

“Words of bile and hatred were hurled in my direction,” he wrote. “Suddenly I was accused of supporting censorship, and bullied into declining this engagement. What started out as one of the happiest moments of my life turned into a shattering display of mob hysteria.”

“With all due respect to the pianist who I was going to replace, one must own one’s opinions and words,” Mr. Goodyear added. “Her words offended many people who perceived her as pro-violence and anti-love.”

Ms. Lisitsa, a naturalized American citizen who moved to the United States in 1991, just before the collapse of the Soviet Union gave rise to an independent Ukraine, embodies some of the complexity of Ukrainian identity politics. While calling herself “an ethnic Ukrainian,” as the daughter of a Ukrainian father and a Russian-Polish mother, she grew up speaking Russian and considers the use of force by the government in Kiev against Russian-backed separatists an outrage. She named her Twitter feed NedoUkraïnka, or SubUkrainian, after reading a disputed translation of comments by the post-revolutionary prime minister in Kiev which suggested that he had referred to Russian-backed rebels as “subhumans.”