Why those tags are made strictly linked?
Female is related to having breasts or a vagina, either for pregnancy, rape or for sexual activity. Human is relating to certain life style or role-play, involving relation of rich and poor or total submission of wage-slave to boss, often associated with semiconsensual, consensual non-consent, or or actively forceful conversation or other activity, for example sadistic\masochistic mobbing. Female may be part of it, but may be NOT.
In addition dildo is a sex toy which can be used for Female or for Human, but is own of its kind.
Linking those tags together sometimes produces inaccurate or even wrong results.
Updated by Rainbow Dash