Sometimes this works. It was pretty easy to explain what can go wrong with nuclear weapons so the public can understand.

Sometimes it doesn't. People have, for decades, expressed concerns about the risks of gain-of-function research on viruses, and approximately 0% of the public understood it until last year.

Many people think Facebook is harmful, and a few people predicted so 15 years ago. Facebook went right ahead and did it anyway, so we know that the warnings were valid. Would you have argued with "Facebook will become harmful" people 15 years ago, demanding they explain exactly what the harms will be? If so, you'd end up on the wrong side of history.