Antonyms for the phrase "are foundation for" would include terms that convey the opposite meaning, such as "are harmful to," "are detrimental to," or "undermine." These words suggest that instead of providing a solid base or necessary support, something is actually causing damage or weakness. Other antonyms might include "are irrelevant to," "do not align with," or "have no bearing on," indicating that there is no connection or correlation between the thing in question and the foundation it claims to support. These words all point to a disconnect between what is being claimed and what is actually true about the relationship between the two concepts.