@A_No_nee_Moose tellement vrai, so true
The « Oh » means a lot as it carries the speaker's feeling. He's really fed up with those bigots' bullshit.
Not only « ta gueule » but « OH, TA GUEULE ! » as you could say « damn, now you shut the fuck up ! ».
Just in a simple « oh ».
By the way, this happened in Groland's Presipauty, a wonderful country. We miss our beloved late President Christophe Salengro.