Livingstone is a bit past it I think. Hopefully Shah will learn from past mistakes. I think a lot of people on the left are very confused about Israel/Palestine, and lump Israel in as a "colonial oppressor" which is a poisonous way of looking at a situation that's much, much more complex than that. London politics in particular seems to be currently involving dog-whistle antisemitism from leftists like Galloway and Livingstone opposed by dog-whistle Islamophobia from the Tories. It's grim.
Some of the things Malia Bouattia has said were anti-Semitic, I think - not high-level explicit anti-Semitism but definitely borderline at best, using tropes like complaining about the "Zionist media" which are dog-whistle terms that date back to the old fascist lie of a global Jewish conspiracy. I don't think they were unforgiveable statements, but at the very, very least for someone in an office like that she should have been able to recognise that she said the wrong thing, why it was wrong, etc - instead she just got very defensive. I feel like anyone who alienates Jewish students as much and as fast as she has is probably not well suited to a job like NUS president.