I agree that any woman who knowingly has an affair with a married man is not innocent. I also agree that it's probably human nature to scream at the 'other woman' - hopefully, after you've screamed at your husband.
Women who blame the other woman entirely are treating their husbands as children, incapable of making their own decisions, and totally vulnerable to the wiles of women.
Sadly we see this all the time. It's not much different from the 'Think of his family' response when women allege sexual harrassment or abuse. For some reason, we're ok aith the man not giving his family a thought before his egregious behaviour. The victim is expected to do that for him.