No. Local genital stimulation is not mandatory for reaching orgasm. The female anatomy provides for multiple erogenous zones any of which may be stimulated to reach orgasm. In fact, it has been observed that in the event of absence or trauma to the external genitalia, existing alternate erogenous zones become more sensitive and new ones develop. Some women can reach orgasm by nipple stimulation alone. I have come across women with absent vagina who are able to reach orgasm satisfactorily by alternate means.

In a study carried out on ritually circumcised South African women, Hanny Light foot Klein reports that these women had retained their orgasmic capacity in spite of the local genital mutilation.