tl;dr in , Spatial claimed that being smart causally correlates with being good. That is, being good does not guarantee that you are smart, but being smart guarantees that you are good (or strongly correlates with it).
I think it's an interesting question that deserves a topic in its own right.
So far, arguments against:
1. No, because many highly successful people are not benevolent.
2. Not if we believe being smart is hereditary, because evolution does not select for benevolence, just look at dolphins.
3. Being cruel requires intelligence.
Not many arguments for. However, I could see how being cruel and self-serving could be a sign of low intelligence. Lying in a job interview might seem like a good idea in the short term, but is probably harmful in the longer term. Recognizing that, planning ahead, to the point of being able to act on it, requires a high level of intelligence and a long-term vision, imho. Being able to look past yourself and society as a whole is, imho, a sign of intelligence.
I haven't made up my mind, because it's difficult to have a clear answer to the question. I feel like the most straightforward way to answer the question would be to look at the statistical average and see if smart people are good. But even then it wouldn't show a causal connection. Maybe it'd be better to take a look at happiness indicators. Often, genuinely altruistic people are happy, and happiness doesn't correlate very strongly with education. So, are intelligent people happy/altruistic?
Looking at dolphins or Donald Trump doesn't seem like a good idea. Looking at SC members doesn't seem like a good idea, either, although I'd say that the smartest people here also tend to be more moral.