Why is "2015 kidnapping and beheading of Copts in Libya" trending?

Wikipedia Overview

The 21 Coptic Christian Martyrs of Libya are Christian construction workers who were killed for their faith by the Islamic State (IS), and subsequently canonized as martyrs and saints by Pope Tawadros II. On 12 February 2015, the Islamic State released a video online showing photos of 21 Christian construction workers—twenty from Egypt and one from Ghana—that they had kidnapped in the city of Sirte, Libya, and who they reported had been killed for their faith. The men, who came from different villages in Egypt, 13 of them from Al-Our, Minya Governorate, were kidnapped in Sirte on 27 December 2014, and in January 2015. On February 15, 2015, the Islamic State's media wing published a video online titled "A message signed with blood to the nation of the cross," in which the 21 captives were paraded on a beach before being beheaded. IS claimed that the executions were in retaliation for the alleged abduction of Kamilia Shehata.
This was not the first time that Coptic Egyptians in Libya had been the subject of abuse for political reasons, a pattern that goes back to the 1950s. In late 2014, a militia group in eastern Libya declared its affiliation with IS and then took over parts of Derna. People allied to the group claimed responsibility for attacks across the country, including the Corinthia Hotel attack in January 2015. On 19 April 2015, IS released another video, which showed the murder of about 30 Ethiopian Christians, reflecting a systemic pattern of the persecution of Christians by the Islamic State.