Ya, I agree with you on this. If we claim that differences in wages, etc. are solely the result of sexism when that isn't the case, then it keeps us from finding and addressing the other causes.
Statistics are a good tool to identify where problems exist, but we still have to address those problems on an individual basis.
That said, most of the women I know -- myself included -- have experienced sexism at some point in their lives, so it certainly does exist and it certainly is a problem. And most of those women did not exaggerate the situation; in fact, they tried to downplay it because sometimes that's just easier then taking a stand and being labelled.