Jeremy Corbyn did enough damage on his own to make people not like him, he held some controversial views and gave the impression he wanted to nationalize even more aspects of the British economy than Atlee's Labour regime did after WWII, then yeah, he's going to attacked by people who'll disproportionately be affected by his economic policies. Just because you personally supported his proposed economic policies if he'd gotten elected, doesn't mean it wouldve worked, long-term.
And no, don't make apologies and try to pretend Labour didnt or hasn't had a problem with antisemitism masquerading around pro-Palestinian solidarity or support over the past 25-30 years. It exists whether you, Geldo, or Corbyn like to admit it or not. There's been too many Jewish ex-Labourites or current Labour members who have forking come forward and said they were made to feel unwelcome or had hateful, antisemitic slurs thrown at them, and Corbyn was one of those top Labour officials who allowed this sentiment to grow or hang around. Ken Livingstone, former mayor of London, and George Callaway have also been accused over the course of their careers of making antisemitic comments, or snide cariurist stereotypical, snide remarks about Jews that got them rightfully blasted.
And so what if he got arrested in anti apartheid demonstrations, quite a few Republican neo-cons used to be left-wing liberals in the late 60's and 70's who opposed the Vietnam War, supported the Civil Rights movement or major progressive movements of the era? You think just because he took part in anti-apartheid marches makes him or others immune or incapable of being possibly bigoted or holding subtle biased or scornful views towards certain minorities? You're not that naive and you're not that stupid, either.