At that show Killing an Arab was sung as 'Killing Kevin Keegan'.
The modification of 'Killing an Arab' to 'Killing Kevin Keegan' caused most likely from Roberts football adoration. On 1980-05-28 the european football champions final was played in Madrid between the english club Nottingham Forest F.C. and the german club Hamburger SV. The english player Kevin Keegan played for Hamburger SV these days, something that Robert seems not to like ... at least that evening.
Notthingham Forest F.C. won the game 1:0