Why is it so hard to separate art from the artist?

Separating the art from the artist is easy for me. Take Joss Whedon, for example. BuffyAngel, and Firefly were foundational to my identity and instrumental in my decision to pursue writing as a career. Before his fall, Joss Whedon was a creator I idolized and resonated with on a deep level. Even my interest in feminism was prompted by him identifying as such.

Though Whedon's scumbag tendencies are exposed for the world to see, it doesn't invalidate the joy I garnered from his work, nor does it prompt me to recontextualize them. Once art it leaves the physical vessel responsible for its creation, it exists independently. 

H.P. Lovecraft would surely hate my Black ass, but it doesn't make his work any less genius. Is his racism tolerable because he isn't alive to spout it? Do the dead get a pass? Since living controversial artists are going to be equally as dead someday, why shouldn't I apply the same philosophy to them in present?

There's one example where I can't separate art from the artist: Chris Benoit.

That's why the video above from the YouTube channel Eyebrow cinema hit so close to home. I can't apply my ability to separate his craft from his crimes. And, if anything, the video forces me to reevaluate my stance on the issue.