Tom Goldman said:
The previous Mario Bros. title had Mario and Luigi knocking turtles over only by smashing platforms below them, but Miyamoto determined that it didn't make sense to be killed by touching a turtle shell with your feet. "We realized it made no sense that you could get killed in Mario Bros. when you jumped on a turtle's back," Miyamoto admitted.
that's the thing miyamoto thought didn't make sense? not the fact that turtles were evil to begin with?
a pretty cool article though, interesting to see how such an iconic game got made.