Preventing the saying of Ameen by some ignorant imams and followers after the recitation of the imam is a part of the practice of the Jews and a sign of their envy towards the followers of the Prophet صلی اللہ علیہ وسلم .

Lady Aisha (may Allah be pleased with her) narrates that a Jew came to the Messenger of Allah (peace be upon him) and said «‏‏‏‏السام عليك يا محمد» ‏‏‏‏ "O Muhammad, death be upon you." The Prophet (peace be upon him) replied: «‏‏‏‏وعليك» ‏‏‏‏ "And upon you as well." Lady Aisha (may Allah be pleased with her) says that I intended to speak, but upon realizing the displeasure of the Prophet (peace be upon him), I remained silent. Then another Jew came to the Prophet (peace be upon him) and he also said that death be upon you. The Prophet (peace be upon him) replied: «‏‏‏‏وعليك» ‏‏‏‏ "Upon you as well." I intended to speak, but I realized that the Prophet (peace be upon him) disliked it (so I remained silent). Then a third (Jew) entered and he said that death be upon you. This time I could not restrain myself until I said, "Death be upon you, and upon you be the wrath of Allah and His curse, O brothers of apes and swine! You greet the Messenger of Allah (peace be upon him) with words with which Allah has not greeted him." So the Messenger of Allah (peace be upon him) said: "Indeed, Allah does not like foul speech and indecency. As they greeted us, so we replied to them in the same manner. Indeed, the Jews are a very envious people, and they do not envy us for anything as much as they envy us for our greeting of peace and for saying Ameen." Imam Abu Bakr (may Allah have mercy on him) says: I have narrated this story from Ibn Abi Mulaykah from Lady Aisha (may Allah be pleased with her) in Kitab al-Kabir.