Manson didn't kill anyone directly. Instead he used 'mind control' to incite his followers to do it for him.
Notice how Brad Pitt's character (military man, Korean War veteran) uses classic Pavlovian conditioning to make his dog attack and kill the Manson clan members.
I think there are a lot of hidden themes and narratives going on in this movie.
Inglorious Basterds was the same.
On the surface, it was a simple reversal of the narrative - the jews got to kill Hitler. Q told us Hitler was a puppet. I think Tarantino was hinting at who actually won WWII.
(re-post as was late last bread)