no, the reverse is that a real friend would confront you and help you correct what he thinks is a mistake, or at least discuss it to understand why, instead of canceling the friendship and worse stabbing you in the back.
if they can't confront someone for what they think is a mistake, then it's them who have no backbone, and potentially also the enabler, because you can't change someones behavior by walking away from them.
Someone leaving after x did something they dont like ... may just be former real friend with a backbone and moral values.