
You know the SA took place AFTER she built a temple with all of Seth's victories imprinted on the walls right? They were great siblings before, which is why she took it at such a great act of betrayal.
If you go back to read it Isis didn't know Seth was being raped, she came in right when he went for the desperate kiss trying to stop Osiris from hurting Anubis. Later, even all through the Horus vs. Seth trials and even when he was being sentenced, Isis felt guilty for sure because deep down she recognized what Osiris did, but she was too hurt by both of them to take back her words and actions then. Seth wasn't all innocent either afterwards, killing women and children indiscriminately to hunt down his sister and nephew. Basically they're all flawed characters, but it stemmed from the manipulative Osiris and of course dumb-ass Nephthys

I repeat : Isis STILL decided to hate her brother and support her husband, that literally what she did, did I lie ? And even tho, the temple was before and she’s feeling guilty, she made her choice! The fact that you tried to quote other people blames as Nephtys or Seth don’t change the fact that she prefered her rapist husband to her brother…

I pretty sure isis didn't preferred Osiris over Seth, but she definitely blames Seth for a lot of things. Also didn't she blame Seth before learning what really happened from nepthys just before she got sealed in that mirror? I guess her hatred for Seth became much more difficult to explain to herself after that.
I feel like we gotta keep in mind that these characters can be hypocritical a lot its what makes them complex y'know
Isis loved Seth like a proud sister. Then Osiris and Nepthys HAD to mess it up, destroying both families and divided this beautiful pair of siblings TT_TT
Seth loved his sister Isis too. In the flashback when he looked into Horus' blue eyes he said their color reminds him of the things he love, like the water of the Nile. We know where Horus gets his blue eyes from...
(/TДT)/ I wish for a happy ending for Seth, Horus, Isis, and Anubis.