It's part of the ideology that drove their actions. How would one even attempt to show the statement was true? Either way, the era called capitalist should be clear.

The question of whether British imperialism drove China away from capitalism is a historical question. Because the Chinese system was mercantilist before British imperialism, it isn't right to say that British imperialism drove China away from capitalism. If old ideology said that, it's incorrect, and we do the world a disservice by repeating it.