Das liegt daran, dass Scart nichts anderes ist, das was Du gepostet hast
ist neben dem composite Signal nur die beiden Lautsprecher Ausgänge R+L.
Hier kannst du mal nachlesen:
The analog section of the DVI specification document is brief and points
to other specifications like VESA VSIS[6] for electrical characteristics
and GTFS for timing information. The idea of the analog link is to keep
compatibility with the previous VGA cables and connectors. HSync, Vsync
and three video channels are available in both VGA and DVI connectors
and are electrically compatible. Auxiliary links like DDC are also
available. A passive adapter can be used in order to carry the analog
signals between the two connectors.
Also -> du musst die sync irgendwie in das composite kriegen, und dafür
gibt es converter.