This made me think of one analogy, that shareholders just want heat in their homes and there are two ways to produce heat: by destroying something (burning oil, the nuclear reaction) or by creating something (fusion). The former is much easier and unless the laws prevent this low effort business, the heating company will happily burn forests, poison rivers and sell the future of the young people if necessary.

Not really. If Facebook (and the rest of them) keep burning bridges and making enemies, in this political climate, they're going to get broken up or even liquidated if enough users leave. That is not in shareholder interest.

And how are profits gained? Ideally, in providing goods or services of value to society.

In a competitive free market the profit incentive is actually the 'who can do the most good for society' incentive.