antisemitic

Dispute between U.K. and Greece over artifacts (Elgin Marbles) that the British rescued years ago and now Greece wants back; should items/lands acquired legally per the norms of a prior period be returned? The riot in a High School in Queens, NY, presumably inspired by a Jewish teacher posting something pro-Israel on Facebook; are pro-Palestinian protesters all antisemitic? Is it OK for the US to support both sides of wars, such as sending supplies to Gaza while sending arms to Israel?