The claim of "xenophobia" is based on suggestions that President Saakashvili may not be 100% Georgian - and thus a slur on whatever else might be in his family tree. If that logic seems hard to follow, bear in mind you're dealing here with the same President Saakashvili
who had his own personal Press Photographer arrested for "spying". The photographer was subsequently released and all charges dropped, after an international outcry.
Sturua has been sidelined as a "shot over the heads" of the liberal intelligentsia in Georgia who have failed to rally to the hardline nationalist fervour of President Suckassvili. As one of the most prominent intellectuals who refuses to join the Saakashvili fanclub, it was inevitable that Sturua would be fired, to "punish" him.