...well. I guess I'm playing devil's advocate for Jae now.
I'm mentally filing that under sexism, but also true
Well, it wasn't him who put himself on the throne. He was a boy when it happened, and Aerea in Maegor's control. Jaehaerys, Alysanne and their mother Alyssa had managed to flee to Storm's End, so that made him the default candidate for the anti-King standing against Maegor. But that was mostly Regnar Baratheon's and Alyssa's doing. And later on, Regnar did change his mind and wanted to enthrone Aerea, but Alyssa went against it. So I suppose what I am saying is, if there is someone to accuse of sexism in this, it is our great-great-grandmother. Though of course she had the stability of the realm and keeping her family together to consider, too.
Jaehaerys is such an interesting and divisive character.
He managed to do a lot of good for the realm and bring stability and peace to the seven kingdoms like they probably have never known before in history.
But his shortsighted choices and worse actions had consequences for centuries and caused incredible amounts of suffering for Westeros and Essos.
What choices would that be? The Dance of the Dragons did not come due to his actions. Aerea and Rhaenys would both have had the better claims to the throne even under Andal law, but Rhaenyra does
not. Her claim comes from the fact that Targaryens aren't Andal, and that there are no codified succession rules for the Iron Throne, and thus the king can decree his heir. Thus, it wasn't like Jaehaerys set a precedent there. Even Aerea or Rhaenys getting onto the throne would have not avoided a war if a situation like Rhaenyra's had come about, because her claim is weaker under Andal law than theirs was. As it was, the Dance was entirely a war within Viserys' family line anyway.
On a political level, Jaehaerys' success is hard to overstate. The population of the 7K doubled during his reign, simply because the realm became so much more prosperous and peaceful. It is on the personal level that things get spicier, though even there... it is such an odd contrast at times.
Because you can't say he was
just sexist. He was perfectly happy with letting his daughters
choose a husband, as long as it was a lord/heir. That is not that usual in Westeros. But on the other hand, he forced Daella to marry at all, despite her obvious mental handicaps and being unsuited for it. Having a 'dimwitted' unmarried aunt around at your seat would also not have been unusual in Westeros, yet force her he did because he thought otherwise she would have no value, which is a pretty shocking thing to say.
And I daresay most lords in Westeros would have reacted similar to the Saera episode. In fact, he even had allowed her great freedoms in meeting with her boys, naively trusting in the supposed omnipresence of servants. If the account in Fire and Blood is correct, he had been willing at first to let the matter slide, but Saera's two escape attempts (fully justified as they were on her side) escalated the matter, whereas other lords might have sent their daughter to the Silent Sisters forthwith. On the other hand, his later statements on Saera were still shocking, and forbidding Alysanne any contact with her was excessively controlling.
Though then again, a lot of that is in fact Alysanne's fault. With Viserra and Gael, their cases are mostly on her, and well, she had a dragon. She wouldn't have needed leave to visit Saera. But back on the original hand that is addressed in Fire and Blood, where Jaehaerys argued Saera would have rather received Alysanne with a slap to the face than a hug. Which is not entirely incorrect... but if Alysanne was so adamant about trying reconciliation, she could have done it. Instead, even with a dragon, she bowed to her husband.
So I think Jaehaerys was sexist, both towards his wife and his daughters, but not in a stereotypical onedimensional way one might expect. And Alysanne, for all she did with the women courts and her laws, has some blame to shoulder for that as well. In fact, I almost dislike her role more than his: She talks a big deal about how Daenerys should inherit, then talks a big deal about reconciliation with Saera, but ultimately, she always meekly follows what Jaehaerys says. All their reconciliations after their big Quarrels (captal q) were her accepting what he had done.
And really, I think the main problem was that their family just got too big, so all the younger children felt unloved to a degree and needed more attention. I mean, that's basically outright stated for Saera in F&B. And it's not like the younger boys turned out all that 'normal', either... well, okay that's just Vaegon, but still, that boy was odd in his own ways.