That is possible in the same way that it is possible that the Green Ajah Quarters have a statue dedicated to Shai'tan as its centrepiece, or that the Sharans have a space program and have sent people to the moon. Actually its less likely - we have been explicitly told that the Red Ajah raising false Dragons is a lie, we have never been told anything about the other two.

And even if you were somehow right, if only a minority know about it, it would be completely irrelevant to this topic. Now, given that I've been arguing this subthread with four different people, it is possible there may be some confusion as to what's going on. As such, here is Fanatic-Templar's helpful recap of this subthread:

Fanatic-Templar: I can't believe that there will be no consequence for Siuan spreading lies ostracizing the Red Ajah.
Cannoli: It would be hypocritical of Egwene to punish Siuan for it, given that she profited from that lie herself.
Fanatic-Templar: Yeah, but you'd expect the Red Ajah to have said something about it in The Gathering Storm or something.
Sidious: The Reds aren't so petty as to expect justice against people spreading lies about them raising up and supporting world-shattering abominations and international criminals.
Fanatic-Templar: You're kidding, right?
Darius_Sedai: Maybe the Reds didn't say anything because they really do support world-shattering abominations and international criminals.
Fanatic-Templar: No.
fionwe1987: Maybe some do.

Which leads us here. I hope this was helpful.