Ridiculous. The guy was a drug smuggler. They ruined his life, like he did many other peoples'. Besides, it wasn't the Singaporean people who decided, it was their government. Surely banning a whole nation because of its government is wrong.
EDIT: Scratch that last point, after reading
this thread, it seems most of the country are for its laws. However, (apparently) 47% of Australians also believe that Nguyen Tuong Van should've been hung too. Doesn't that mean 47% of Australia should be banned?