This is a very idealistic view of history. Ideology did not create material conditions, material conditions created ideology (and ideology was used as a tool to reinforce material conditions)
The slavery, genocide, capitalism and colonialism came first. Then liberalism was created to justify it. And I do want to emphasise that all of those 4 things were justified using liberal logic, that was the point of liberal logic.
The first liberals deemed the “unenligtened” to be subhuman, incapable or governing themselves, worthy of being treated like livestock and as fundamental threats to the ruling order. This was their justification for doing everything they did, you can read their writings on native Americans and Africans and see exactly what classical liberalism was all about.
Later waves of liberals ended up using liberal logic to abolish slavery. Great. But the reason they did this was because the capitalist mode of production had superceded the slave mode of production. The surplus of proletariats hated competing with slaves and having their wages be reduced. Meanwhile the northern bourgeoise often had friction with the southern planters since the planters were rentiers extracting wealth from the whole economy like parasites.
Modern liberals now proclaim themselves to be great champions of “liberty” (the liberty for the bourgeoise to buy property), but they by in large continue to support capitalism and western imperialism*. And frankly, why wouldn’t they? That was what the ideology was created for.
*you can see this in their insistence upon using “white man’s burden” arguments whenever foreign intervention comes up
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