That's a rather blanket statement. Not all indigenous knowledge is devalued. Much attention is being paid to traditional or local knowledge and how it can inform mainstream science. However, not all indigenous knowledge claims are correct either, and some knowledge cannot be generalized beyond the local conditions in which it applies.
And some traditional local knowledge is just a dead end: Yoruba mathematics is at best serviceable only for small and imprecise transactions in rural farmers' markets, despite the grand claims some educators make about the value of ethnomathematics.
That's a rather blanket statement. Not all indigenous knowledge is devalued. Much attention is being paid to traditional or local knowledge and how it can inform mainstream science. However, not all indigenous knowledge claims are correct either, and some knowledge cannot be generalized beyond the local conditions in which it applies.
And some traditional local knowledge is just a dead end: Yoruba mathematics is at best serviceable only for small and imprecise transactions in rural farmers' markets, despite the grand claims some educators make about the value of ethnomathematics.
Science doesn't devalue all forms of indigenous knowledge at all. Indigenous medicine, for example, has always been the foundation of modern medicine and cured many ailments. However, scientists devalued indigenous knowledge systems which relied on untruth such as witchcraft, sorcery...