I think one of the reasons is that because more and more people
do it, it becomes more morally "acceptable" to do so.
Another reason could be that people see it more as a monetary
contract. If a company overseas willing to pay the monetary penalty
of breaking a bond offers to hire the scholar after his/her
education, most people would definitely take the opportunity of
enjoying a higher pay and the prestige that comes with it, as
opposed to coming back to work in Singapore.
One other reason which I believe to encourage this, is the
government's habit of imposing hefty fines to enforce laws. The
unfortunate side effect of this is that it breeds the mindset in
people that any contract with the government is purely monetary.
The unconcious thought process for most people when they break the
speed limit, is that its bad not because its wrong and dangerous,
but because they would have to pay a heavy fine. Same way, when
someone break his/her bond, its bad not because its (supposedly)
morally wrong, but because he/she would have to pay the expensive
penalty. So when there's an opportunity to circumvent the monetary
disincentive of breaking a bond, the scholar would most probably
grasp it.
As for people who can afford to pay for their own overseas, but
choose to accept a bond with the intent of breaking it as they
would be able to pay off the penalty, it is probably due to the
"prestige" of studying overseas on a scholarship, since money isn't
a factor to them. A reason for this would be pure selfishness,
nothing more.
That's all I can think of at the moment. Let me know if it helps
