I agree with you a 100%. And there is less risk of cervical cancer, STDs, and HIV.
The most important risk factor for cervical cancer is HPV infection. HPV is a sexually transmitted disease.
If someone proposed cutting off part of a girl's genitals in order to protect adult men from sexually transmitted diseases, most people would be outraged.
In my opinion there is no ethical difference between cutting off part of a boy's genitals in order to reduce the risk of adult women who choose to practice unsafe sex and cutting off part of a girl's genitals in order to reduce the risk of adult men who choose to practice unsafe sex.