Capitalism is a tool intended to fix these very problems!

What definition of capitalism are you using here? Because I think most commonly-accepted definitions definitely do not assign this as an intention of capitalism.

Strong regulations, moral actors, and careful control can fix many of capitalism's problems. But the kind of unfettered capitalism that, for example, anarcho-libertarians espouse would certainly not lead to less environmental devastation, oppression/wage-slavery, and/or mis-allocation of resources.

Historically I think most people would agree capitalism is in a better state than it has ever been. Capitalism as practiced in the late 19th/early 20th century was very different from our understanding of it today and was much much worse across most dimensions. That is a result of evolving regulatory frameworks making capitalism more compatible with what we define as happiness, justice, and morality. Hopefully we can continue curbing the issues of capitalism while encouraging the things it is good at (like making numbers goes up and creating lots of shiny things people like).

It was worse to be a farmer owned by your local feudal lord, no?

Definitely true. But this is not a problem for most capitalist critiques; that the current system is better in some ways than others doesn't mean it also isn't bad.

This is a very difficult thread for me, because you’ve immediately started it from what feels like an insincere position of insisting on the polite debate of a system that has actively harmed innumerable people. And continues to do so.

While I don’t deny that polite debate is preferable to flame wars and anger, you’ve come in here to try and debate a subject that raises passions.

And the reason I say this from the outset is because of comments like this;

Environmental devastation is an externality because the rules haven't been defined properly-- if the rules of capital ownership around environmental concerns were clarified (through some system of carbon emission limitations and carbon credits), then I'm sure capitalism could optimize for a good environmental outcome. A bad thing, to be sure, but not the fault of capitalism.

The ‘rules’ in this case have been defined. Most countries have rules in place to govern the environmental impact of industry. But companies led by capitalists ignore those rules as far as they can, which is how we are where we are.

Here in the UK, we have record breaking amounts of sewage and pollution in our rivers, because our water companies are run by capitalists to turn a profit. The fines from the government are ultimately paid by those of us who pay our water bills. The people in charge continue to pay themselves and their shareholders well.

And this is where capitalism fails miserably, in my opinion. As noted in another comment in here: capitalism is built for profits, not for human comfort. Businesses who pollute know full well that they should reduce their emissions, clean up their waste, and be better global citizens, but left unchecked, they won’t. You admit yourself in that quoted comment, that capitalism needs a set of rules around carbon credits and such to address the problem. They know there’s a problem, but are waiting for governments to force them to clean up their act.

That doesn’t make me feel that capitalism is the kind, loving economic system we all need. Quite the opposite.