In our present capitalist society, raw materials, plants and animals are considered externalities. The earth is not a legal person in the present situation. The problem is, therefore, the earth has no rights, the earth is of nobody and of everyone. In the economy, the earth is considered as an externality that you need to run your business. The problem that arises is that raw materials are extracted plants and animals patented and apparently becoming the property of a small number of companies.
This property right does not require any work to creat, it is naturally present, such as oil. We know the oil barons. In the middle east you can find them, but also in Russia or other parts of the world. The situation is that this wealth is now owned by a small number of people who essentially get things out of the planet to add value to the economy and then become rich. What is wrong with this is that the wealth has been created by the earth. So the earth must also receive this wealth and not a few individuals that just extract it.
The capitalist system assumes that only legal entities have rights within the system. Because the earth is not a legal person in the capitalist system (which is made up by humans), the situation arises that the earth in the system is externality and also has no rights.
Because the earth is not a legal person and therefore has no rights, the earth can not do anything in the capitalist system. The solution is therefore to give the earth rights within the capitalist system, and you can do this by making the earth a legal entity. This gives the Earth rights and can fight the earth for its interests just as companies do in the capitalist system. If your point is that the earth is not human then the argument is, for example, a company is also not a person but a legal entity, persons run the company, the same construction can also be taken into consideration by the earth.