White supremacist anti-Muslim narratives generally refer to Islam as an invading force that isn’t just incompatible with Western society, but is also an active threat to Western society and cultural norms. In this context, white supremacists have used Crusader-themed imagery and rhetoric, like the Jerusalem Cross, the Knights Templar and “Deus Vult,” as dog whistles to promote anti-Muslim hate
there’s specific reference to the Jerusalem Cross here. https://www.mccaininstitute.org/wp-content/uploads/2021/10/white-supremacy-and-anti-government-groups-read-ahead-materials.pdf The Adl link is to look up other terms in general