"Hah hah, I've worked out that your claims of magical power are fake, you're just using faeries!" seems like a monumentally stupid thing to say to the woman who can have you killed by her guards on a whim. Doing so reveals that you know too much to be allowed to go free, and keeping you locked up for a prolonged period of time wouldn't benefit her at all. She'd have you killed pretty much on the spot.
I mean, Vanessa is one of those people who doesn't have middle gears, and she can sometimes be presumptive (she assumed she knew who Kali was as a person, just because she knew who her father was) but she's also been shown to be more willing than most people to change her opinions/beliefs when presented with new information.
But the thing that always fascinated me when people come here and complain about her behaviour is that SHE'S OBJECTIVELY RIGHT about how the elves are being treated like shit, and yet every now and then, someone comes along and says she "reminds me of apologists who preach about change", while ignoring that the thing she wants changed is literal slavery. Not because she's an elf and would personally benefit from their freedom, but just because she sees how they're treated and knows it's wrong. She is a person of moral convictions, who has the courage to stand by her principles.
Would many people in-universe find her annoying? Absolutely, because she's a constant reminder that their lives are built on the subjugation and exploitation of nearly a billion people, and she's unwilling to not be quiet about that fact. and it can be wearying to be around someone who's running at 100kph all the time. But she's still right.
