"says the women who use these groups aren't doing anything wrong as long as what they're sharing is their opinion or the truth" what possibly could go wrong with that?
I understand the sentiment, creating a space where women could feel more safe when meeting with complete strangers by asking other woman. But this has so much potential for abuse that I cannot really see how it could have a positive impact. A crazy ex can already ruin the social life of a person by spreading lies to your inner circle (people of all genders are perfectly capable of this), but if this kind of things gain traction, they would be capable to remotely ruin any new attempt of creating a new life far away.