Dozens of musicians and panelists have withdrawn from the South by Southwest Conference and Festivals in Austin, Texas, to protest sponsorship by the U.S. Army and defense companies as pressure grows against the U.S. military’s support of Israel’s war against Hamas in Gaza.More than 80 artists and panelists at SXSW had joined the boycott by Wednesday, according to one of the organizers, the Austin for Palestine Coalition.Ibrahim Batshon, a Palestinian American and the chief executive of BeatStars, a digital music-licensing platform and longtime sponsor of the music and technology…