If you accept defamation laws (and defamation laws are a thing in Singapore and many other places), then the question is whether you actively participated in the creation or dissemination of slander (again, assuming that creation and dissemination are both illegal).
We in the tech world have optimized various mechanisms to enable sharing information- we have gotten so good at it that our users don’t pause for a moment and think about their responsibility they bear when hitting that share button.
It’s like picking up cleanly packaged meat from the grocery store or filling up on gas from a gas station- the experience is so clean and polished that one doesn’t really think about where the meat/crude oil is coming from and what it means to be paying for it.
I think the courts held that one is responsible for what they share. It isn’t “merely” sharing a news article on facebook - the person had to decide to hit that share button.
Now, there are a lot of things wrong with this. But most of the problems come from having some defamation law to begin with.
I take issue with the law itself, but this interpretation of it doesn’t bother me.
IANAL, and I don’t know if dissemination is somehow different from creation in defamation cases. I expect it has to be - otherwise “Mr. X is a pedophile” can be illegal while “I heard that Mr. X is a pedophile” isn’t. Which seems dumb if one’s intent was to make defamation illegal in all ways.