Look at the Talmud.

Sanhedrin 54b:

The Gemara asks: What does it mean that the Torah does not deem a younger boy to be like an older boy? Rav says: It means that the Torah does not deem the intercourse of one who is less than nine years old to be like the intercourse of one who is at least nine years old, as for a male’s act of intercourse to have the legal status of full-fledged intercourse the minimum age is nine years. And Shmuel says: The Torah does not deem the intercourse of a child who is less than three years old to be like that of one who is three years old.

https://www.sefaria.org/Sanhedrin.54b?lang=bi

Ketubot 11b:

"An adult man who engaged in intercourse with a minor girl less than three years old has done nothing, as intercourse with a girl less than three years old is tantamount to poking a finger into the eye."

https://www.sefaria.org/Ketubot.11b.6?lang=bi

They think they are justified by that disgusting abomination of a book. Not even the depravity of Islam explicitly condones this disgusting degeneracy.