You don't know that. It's a theory, but as you said, how can you compare.

I can tell you that for their female partner's pleasure to enjoy sex as it was meant to be enjoyed, it makes no difference. I have it on very good authority.

Most of our sexual pleasure stems from the mind rather than the genitals anyway. If you believe strongly enough that your sex life is reduced because of circumcision, then it will be, just as women who adopt sexual shame beliefs from religion often become frigid and unable to enjoy it.