It goes without saying that the Bible condemns witchcraft. Therefore, Wicca is condemned because Wicca is witchcraft. But, unfortunately as a result of some of the Biblical passages about witchcraft, some Christians have killed witches. The Burning Times is a term Wiccans use to describe the persecution and killing of witches in the 1500's and 1600's. The truth is that Christians were involved in this atrocity citing Old Testament passages as justification for their actions, i.e., Exodus 22:18, “You shall not allow a sorceress to live."
The OT passages were written under a theocracy, that is, they were written during a time of Jewish theocratic rule where God told the Jews to restrict themselves from many false teachings and practices. The reason for this and the harsh punishments for violating those rules was that such false practices could ultimately undermine the coming of the Messiah, and thereby jeopardize the salvation of all people. This is why you see such harsh treatment by God upon so many in the Old Testament. Since God was using the Jewish people to be those through whom the Messiah would come, it was necessary to keep the messianic line pure.
But, since the Messiah has come, there is now no more threat to the messianic line, and we are free to "turn the other cheek" and to love people as God loves them (Matt. 5:43-48). Unfortunately, many of the Christians of the 1500's and 1600's did not apply love and kindness to those who practiced witchcraft. Instead, they used Old Testament law while abandoning New Testament grace. The result was that thousands were killed. This is why many Wiccans see the past actions of the Christian Church as well as the present behavior of many Christians as evidence that Christianity is false. If this kind of behavior is what Christianity produces, then, the Wiccan would reason, why not turn to nature religion? Oftentimes, all that Wiccans and pagans have to judge Christianity by is the bad behavior of those who claim to be Christians. This is not good.
If you are a Christian dealing with a Wiccan, you need to be respectful of the individual, listen to what is said, and lovingly offer correction. Outright condemnation and anger only pushes a Wiccan further into his or her deception. Jesus forgave the adulterous woman, forgave the disciples' sins, and taught us to be loving and kind. That is how you are to be as well.
If you are a Wiccan, please understand that we mean you no harm and our concern is for your eternal salvation. We believe the Bible is true not because of subjective feelings and bigotry but because of the work of love and forgiveness that the Lord has brought into our lives. We condemn the actions of those who claim to be Christians and walk in hatred and abject condemnation.