I agree this is a difficult spot to be put in: be quiet (or nice) and nothing changes, or be loud and aggressive so that people are forced to take notice. I don't wish that kind of double-bind on anybody.
In this position, some people seem to find a third alternative: be fierce and yet unflinchingly kind. Make a lot of noise, but be charitable with your opponents so that their good side has the opportunity to come out. People change on their own time. We can't force it.
Truth be told, it takes considerable wisdom to pull this off, and it's unfair to expect that of most people. But the alternative is to become increasingly bitter and caustic. That ends up making you feel increasingly self-righteous, but also increasingly isolated (which then feeds the self-righteousness, in a vicious cycle). It doesn't actually help the cause.
She doesn't deserve contempt for falling into that trap. Like all of us, she deserves compassion. But it's okay to point out that her behavior is unhelpful. We, too, should not fall into the double bind of keeping quiet about it versus responding aggressively. We can be kind and firm.