Voris characterized Gregory as a "liar" for speaking out on the day of Trump's visit rather than on the day he declined the invitation.
He also claimed that "various priests who have been in his presence for more than three seconds" call Gregory "African Queen."
Church Militant did not respond to CNA's request for comment.
Christine Niles, senior producer at Church Militant, in a June 12 tweet repeated Voris' claim that the nickname is used by clergy and seminarians- none of whom Church Militant has named- behind Gregory's back.
"'African' is his race. 'Queen' is a common term used by homosexuals to refer to other homosexuals. Thus, 'African Queen.' It's the name bandied about by clergy and seminarians about Abp. Gregory for years," Niles wrote.
In another tweet, she claimed "famed sex abuse expert and former priest Richard Sipe said [Gregory] is indeed homosexual."
Church Militant had on June 5 published a report claiming that Sipe had deemed Gregory an "active homosexual." This appears to be a reference to a 2006 document from Sipe in which he presented "A Preliminary Review of Sexual Orientation of Some American Bishops," and in which he noted that the list implied "no accusation of sexual activity on the part of anyone named."
Separately, Niles on June 12 defended the moniker "African Queen" as a "movie reference" to the 1951 film "The African Queen."
She dismissed myriad calls online from fellow Catholics to remove the video, many of whom urged Voris and the rest of the Church Militant staff to "go to confession."
"We're Catholics in good standing," Niles tweeted June 12.
In the same tweet, Niles said the archdiocese "has a habit of lying, and accused it of falsifying an allegation of rape against a priest, adding that "we don't really care what their opinion is about us. It's irrelevant," Niles said.
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The priest in question is Father Eduard Perrone, who the archdiocese temporarily removed from ministry in July 2019 and brought under a canonical investigation for an allegation of groping a former altar boy. The priest denies the allegations.
Church Militant has frequently accused the archdiocese of fabricating a rape charge against Perrone. The Archdiocese of Detroit has not responded directly to those allegations. Several staff members of Church Militant, including Voris, have said or posted online that they attend the parish Perrone led.
The conflict is not the first clash the group has had with American bishops.
In 2011, the Archdiocese of Detroit said that Church Militant, which was founded as "RealCatholicTV," should not use the word "Catholic" from its name. The group made a name change, while maintaining that the archdiocese did not have authority to require it, because the site was owned and headquartered elsewhere.
In 2015, then-Philadelphia Archbishop Charles Chaput said Church Militant "sow division wherever they tread," while the Philadelphia archdiocese said the "sole desire" of Church Militant "is to create division, confusion, and conflict within the Church. Actions of that nature run contrary to Christian tradition. Their reports are not to be taken seriously."