“Free Gaza” demonstration by Im Tirtzu Zionists took a stab at “Boycotting, Divesting and Sanctioning” (BDS) artists they charge are doubling as terror supporters and “traitors” in Israel. Liberals and anti-Semites dominating those professions haven’t stopped fulminating and blinking in astonishment since the announcements were made last January. Controversial (a 21st-century word for “conservative”) group Im…