It's legit. Galloway has been playing into reactionary shit in order to grow and this inevitably attracts very bad people and candidates. It's a dead end strategy that will only really succeed in maintaining his own relevance and not really help achieve socialism.
With that said antisemitism has risen among totally normal people in the UK as well. I met a doctor the other day who just blatantly said the jews are bad in conversation with me (not just the israeli population). The conflation of jewishness with the state of Israel is responsible for this alongside the absolutely massive anti-israel attitude across basically the whole country.