Commento su Levitico 20:15

ואת הבהמה תהרגו AND YE SHALL SLAY THE BEAST — If the man has sinned, what sin has the beast committed? But because the man’s opportunity to stumble (to sin) was occasioned by it, therefore Scripture says, “let it be stoned"! How much the more does this principle apply to a human being who knows to distinguish between good and evil and yet brings evil upon his fellow-man by inducing him to commit a sin. In a similar way you should explain: (Deuteronomy 12:2) “Ye shall utterly destroy all the places [where the nations… served their gods… under every bushy tree]" Now is not the following a logical conclusion? How is it in the case of trees which can neither see nor hear? Merely because an opportunity to sin was occasioned by them Scripture says, "Destroy, burn, exterminate them!״ One who makes his fellow-man deviate from the path of lifeto the path of death, does it not follow all the more that he should be punished? (Sifra, Kedoshim, Chapter 11 5; cf. Sanhedrin 54a, 55a.)

ואת הבהמה תהרגו, “and the beast you shall kill.” Rashi, following our sages, asks the rhetorical question why the animal should be killed seeing it had not committed a crime? The answer given is that seeing the animal was the catalyst leading to the sin by the human being involved in the act the Torah decreed that it be stoned to death. You may apply some logic here. If even an animal which is unable to distinguish between right and wrong is executed, how much more so will execution be the penalty for a human being who does know right from wrong. When a human being is the cause of a fellow human committing a sin, he is certainly culpable for what he did.
We have a verse in Deut. 12,2 where the Torah commands us to destroy all the sites on which idolatry was performed by the Canaanites prior to the Israelites coming to the Holy Land. This provides us with a similar reason of why humans guilty of idolatry will be subject to the death penalty. If even trees, which most certainly were totally passive and had no knowledge of something sinful being performed involving them, are subject to destruction on account of this, how much more so are human beings who were the cause of another human being induced to worship idols through deceiving such a person, subject to execution for their deeds?

ואת הבהמה תהרוגו, “and the beast (involved in this perversion) you have to kill.” The reason is in order to prevent it to be used in the same manner again and thus cause a Jew to commit this sin.