Anti-zionism is not anti-semitism. Zionism itself is anti-semitic. It is the ideology of creating Israel as an ethnostate, it was a fringe of jews at one point in time but the people who wanted to kick the jews out of Europe popularised and supported its growth(hence why it is itself antisemitic in origin).
Anti-zionism is literally just being against the state of Israel as a jewish ethnostate and apartheid regime. It is also supported by a very large number of internationalist jewish organisations.
As for mossad having funded certain people currently organising inside the labour party, this is just factually correct. We have the receipts and it’s openly known.