There are many problems with such explanations, including but not restricted to:
1. Much of the “evidence” cited in support of discrimination does not actually demonstrate discrimination. For example, some gender gaps in funding and in graduate admissions have been conclusively shown to result, not from discrimination, but from the fact that women disproportionately apply in more competitive fields.
2. Some of the “evidence” is correlational (e.g., correlating beliefs with some gap), and is interpreted as causal, without any evidence of causality.