All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
We have not come across any statement of the scholars about this matter, and there might not be any apparent reasons other than the fact that Allah predestined and decreed this to be the case.
Some of the Prophets may not have been killed because they were of great status amongst their people, or that they had tribes who protected them, or for other reasons. Allah Says about the people of Shu’ayb (what means): {They said, "O Shu'ayb, we do not understand much of what you say, and indeed, we consider you among us as weak. And if not for your family, we would have stoned you [to death]; and you are not to us one respected."} [Quran 11:91]
Al-Qurtubi said about the above verse in his Tafseer: “The term "we would have stoned you” means, we would have killed you by stoning you. Whenever they wanted to kill a person, they would stone him to death. The tribe of Shu’ayb was upon their religion (those who wanted to kill him).” [End of quote]
However, we do not mean by this that the Israelites were the ones who had the desire to kill Shu’ayb . The people of Shu’ayb were the people of Madyan who were Arabs and lived in Madyan, which is a village in the land of Ma'aan on the outskirts of the Levant from Al-Hijaaz side. So, his people were not from the children of Israel.
You should know that most of the Prophets who were killed by the Jews or whom the Jews tried to kill belonged to the children of Israel; they were from their people and from their race. They had killed Zakariyya (Zachariah) and Yahya (John), may Allaah exalt their mention, and tried to kill ‘Eesa (Jesus) and all the three of them were from the children of Israel.
Allah knows best.