You mean like we forbid murder and murder still happens? Do you even have a brain?I mean, think about it...
Some Popes have recently apologized for the evils Christianity committed in order to gain power, and it took well over 1000 years for them to even admit those evils.
But they didn't change the religion and forbid these things in the future. They just said they were past transgressions and should be forgiven. The religion itself remains the same.
So if the religion says to do it again... then there is nothing to stop followers from doing it again...