Corbyn has long opposed a number of systems and regimes which oppress groups of disempowered people.
And therin lies the problem. His list of bad regimes is highly selective. Won't hear a bad word about Cuba, Venezuela, and until recently Ecuador, where President Lenin Moreno sent Assange packing and has to deal with so much of the economic fall-out from the postruing Marxist claptrap of his predecssor. His taking sides with would be President-For-Life-Or-Possibly-Longer Morales in Bolivia after his supporters tore up the constitution and rigged the election is another.
One example of this, among many, is that he's been vocal about the racist policies of the current Israeli government, and the effects on Palestinians (who are the oppressed people in this case).
What racist policies? One-fifth of Israelis are Arabs, many of them Bedouins and Christians who are persistently persecuted by both Fatah and Hamas, the former more subtly, the latter more directly.
There are black and brown Israelis from every continent. Where is the racism, in contrast to the Hamas Charter?
No one persecutes Palestinians like Hamas. They are murderers, torturers and absolutely criminal gangsters. Along with Hezbollah and Islamic Jihad, they kill more Palestinians than Israel ever could.
Netanyahu is disgusting, but he is, or was, eleceted, and now there is going to be a trial and the Likud PM may go the way of the last Likud President and end up in jail, because Israel unlike any Arab state has the rule of law and an independent judiciary. Far from perfect, but stratospherically better than even the best Arab country, Jordan where honour killings and forced child-marriages abound.
And whilst we're on the subject, why do all those Palestinians remain in camps when they could all go to the Gulf and get jobs? (Or rather if they could...)