common root of evil

In Joanna Hoyt's blog, Living as if the Truth was true, I read this and have been sniffing it carefully, wondering if it was for real.

 ... weighing the evil I do against that done by someone else is basically meaningless, because we are not separate. Just as our courage, love, integrity are not ours alone, are from God, flow between us in ways seen and unseen, so also our cowardice, our hate, our falsehood come from one root and pass between us openly and hiddenly. And it seems to me that to deny this connection is to consent to a lie, to make an opening for hate, to strengthen evil.