The first time JR was shot, yes, considering all she had been through. She was a sick woman, inho, and needed medical/psychological help. Also, there was still the possibility she hadn't done it.
The second time when she actually did shoot JR and admitted it, I would have told her to neverv show her face on Southfork ever again. When Miss Ellie told Sue Ellen she was "disappointed" with her, I was shocked. You're disappointed when your favorite show is canceled, not when someone shoots a family member I wanted to see Miss Ellie unleashed. Where was that Mama Grizzley Bear I expected? Yes, SE was her daughter-in-law, but JR is her son. The first time she had severe alcoholism and JR threatened to lock her up in a sanitarium for life, and as I said, the question of her guilt still seemed up in the air. The second time she broke into JR's suite with a man who attacked him. Big difference.