Professional protester Greta Thunberg was arrested Tuesday in Central London while part of a mass gathering backing the Palestine Action terrorist group. The 22-year-old Swede was detained as she expressed support for the proscribed organization. In a video shared by the Prisoners for Palestine protest group, Thunberg can be seen holding a sign reading “I support the Palestine Action prisoners. I oppose genocide” at the demonstration outside the central London offices of Aspen Insurance. Two activists sprayed red paint over the front of the building before police arrived and made arrests. Prisoners for Palestine said its protest had targeted the...