> It's very violent because it gets violently repressed by capitalist forces

Millions of Soviet deaths; millions of Chinese deaths; deaths from the Khmer Rouge....these are not "violent capitalist repression". Capitalism isn't a total system. It's a voluntary exchange system, where people who provide the most get the most.

> What value do people inheriting wealth provide?

That money was earned by providing value.

> What value do high frequency traders provide?

If listing a company on a stock exchange isn't valuable for companies, then they wouldn't do it. But it is. So they do.

> What value do speculators of all sorts provide?

It depends on your other examples of speculators. If you see how they make money, then you'll probably have your answer.