It didn't work for Netanyahu when he tried the propaganda that Palestinian Arabs are never really angry about specific acts taken by the Israeli government, but rather at the existence of Israel itself. He faced significant backlash for his false claims.
https://time.com/4084301/hitler-grand-mufi-1941/I think expanding to other countries will dilute the effectiveness of the student campaign - the accusations of antisemitism is useful publicity and keeps the spotlight on the issue of Israel's war crimes.
I think the Oxford students have the right strategy of focusing on Israel at this particular time i.e. while the UK government and businesses are politically and financially supporting Israel while it openly carries out war crimes through its collective punishment, starving, bombing, cutting off fuel and creation of a humanitarian crisis for Palestinians.
Sure the UK government could argue that Britain has its own history of racism, colonisation, brutality and collective punishment so we shouldn't be too hard on the Israelis or any other democracy for being as brutal and violent as Britain was in the not too distant past, as that could be seen as antisemitism.
Netanyahu has even tried this line of argument with comparisons to Churchill (an imperialist who campaigned against Indian Home Rule because he saw the "dusky races" as inferior) and the US bombing and invading Afghanistan after 9/11, which didn't really work out for the US.
Not sure why Netanyahu is bringing up Afghanistan - not only did hundreds of thousands of people protest against bombing Afghanistan so it's clearly not antisemitism driving protests, but the ICC is investigating whether to indict the Taliban, the Afghan government and the US military and CIA for war crimes during that conflict, so it reinforces the point that the IDF and the Israeli government should be investigated by the ICC too.
https://theconversation.com/did-the-us-commit-crimes-in-afghanistan-international-prosecutors-want-to-find-out-133590Probably Netanyahu wants to warn the US politicians that they could be held similarly accountable for breaking international law and bombing and murdering people if white people especially don't all join forces to ensure no one is allowed to hold the rich and powerful accountable. The ICC prosecutor has a dusky hue so that probably already undermines his position in the eyes of many.
The antisemitism argument doesn't work, even if it is useful publicity, as many previous student protests have spoken out against British historical colonialist activities and their legacy of discrimination and inequality. Not surprisingly the students have added Israel as a colonialist entity to the list while Israel's Zionist policies focus on creating and expanding a Jewish state through colonisation and while Israel is carrying out those same atrocities today while touting its credentials as a democratic country.
Not sure why Netanyahu or any democratically elected leader would expect a free pass for terrorism - must be the colonial mindset of Western superiority - if your skin is relatively white, you're allied with the West and you colonise and brutalise people it's all quite civilised and can be overlooked....except if you're white and Russian, in which case immediate sanctions and an ICC arrest warrant of course.
Hamas was democratically elected to power too in 2006 largely due to the corruption, incompetence and brutality of their opposition, Fatah, yet we're not saying the ICC can't indict the leader of Hamas for terrorism just because Hamas wins an election.
https://www.snopes.com/news/2023/11/01/majority-palestinians-gaza-elect-hamas/It's a bit difficult to take the antisemitism accusations seriously while there are lots of Jewish people protesting against Israel's war crimes.