defending the absolute dregs of society

It read to me as if she was defending ordinary decent Muslims from being blamed for this atrocity, and from the assumption that they are not as appalled and disgusted by it as anyone else.

Often enough when it appears that a terrible crime against some innocent has been carried out by a Black person, or by a Jewish person, this has been used as a way of stirring up hatred and violence against Blacks or Jews in general. And people objecting to that have indeed been accused of having no regard for the original victim, and have been accused of "defending the absolute dregs of society".