One Of my other worries about having more sith eyes is that even Anakin of all people, Only had sith eyes for maybe… 5 or 10 seconds in episode 3, not even when he was murdering children so I’m worried about it being unprecedented.
Well, following sequel logic it would be because she is related to Palpatine, who has Sith eyes at all times. Definitely not a good reason, but I could see it.
Also, Kylo just hurt (or possibly killed) her first friend, so it makes sense she’d be super angry.