WHO compared past an present HIV rates of whole nation? But that doesn't mean circumcision is preventing HIV transmission. Other factors like public awareness are possibly preventing HIV. WHO had to compare HIV rate between circumcised and uncircumcised guys. Several research done in western countries found no difference in HIV rate between circumcised and uncircumcised men. Even condom can't prevent HVP. So circumcision has nothing to do with Penile cancer. In normal situation an uncircumcised boy is unlikely to get infection as he has natural protection (smega that prevents germs)
Circumcision desensetise glans and removes most sensitive part of penis
Circumcision is not only about foreskin. It's also about consent.