When you plant lettuce, if it does not grow well, you don't blame the lettuce. You look for reasons it is not doing well. It may need fertilizer, or more water, or less sun. You never blame the lettuce.
Yet if we have problems with our friends or family, we blame the other person. But if we know how to take care of them, they will grow well, like the lettuce. Blaming has no positive effect at all, nor does trying to persuade using reason and argument.
That is my experience.
No blame, no reasoning, no argument, just understanding.
If you understand, and you show that you understand, you can love, and the situation will change.
In the realm of politics, we blame poor people for being poor, desperate people for being deperate, and people who resort to violence (when they truly have no other recourse) for that too.
I think the "lettuce in the garden" is a wonderful metaphor. Next time I find myself getting upset with someone I'm going to remind myself, "Don't blame the lettuce!"