My therapist says it's a fair comparison, it's not a movie about "oh he's just human", it's "look at the assholishness of this human".
My therapist said that since Musk has killed a lot more people, the comparison is actually unfair to Manson.
Has he? I don't think so, if you have clear evidence you should tell the authorities, he should be in prison if he has committed murder as you claim. However falsely accusing someone of a high crime could result in you being charged so tread carefully.
Your therapist and reality don't meet often, do they.