Oh really, you obviously don't know the rules. Under rule 423(j), subsection (xiii), a Ferrari can be penalised only if the resultant penalty has no effect on the World Championship. Thus a drive through penalty in Valencia would have cost him the race, so was strictly prohibited, while the drive through in Singapore didn't cost him anything and therefore was imposed. So you see the Stewards were perfectly consistent.
Similarly, when he spun later in the race and pulled away straight into Sutil's path, causing Sutil to crash and a safety car situation, anybody else would have received a ten-place grid penalty for the next race. But clearly that would have offended against rule 423(j), subsection (xiii), so quite rightly no action was taken.
If you don't know the rules, I can't see why you bother to watch SoapF1, Harry Burgundy. Not for the racing, surely?