There are following implication to that important and curious question..
1: i second the opinion my forum fellow that low salaries make them so as they realize that they have earned that position after a cut throat competition and they must be paid handsomely and when they don't get as much as they deserve they indulge accepting bribes and like things..
2: A CSP is always prone to political pressures, some can get away with it but others can't..
3: when they join, they see their seniors doing this so after resisting a little they become accustomed to it following a famous saying "Do as the Romans do"