You may have been impressed by the way they keep order, but you weren’t chewing a stick of Juicy Fruit gum at the time, which is illegal there.
I lived in Singapore for 4 years. It’s not illegal to chew gum in Singapore. It’s illegal to sell gum. It’s illegal to litter which includes dropping gum anywhere, but in the garbage bin. You can possess gum and chew it all you want.
You’re wrong—that’s not true anymore.