Regarding Corbyn’s remark, here is his speech (which, again, no-one hardly ever links to). The speech was made in 2013. For five years no-one cared much about what he said; then suddenly everyone is aghast:
And the only thing people seem to be discussing in relation to that speech is the phrase about Zionists not understanding the British irony despite being born in Britain. There’s a recent letter published in The Times about this very phrase:

The very beginning of the letter is showing how distorted the whole debate is. Corbyn’s speech was about the state of Israel and the injustice done to the Palestinians (why people from the other side of the world care so much about that, I don't know, but for some reason they do). The author of the letter starts with the words "I am Jewish", re-framing the discussion from a historical, moral, and political into a nationalist/religious one.