I'm Jewish and I agree but... it's complicated.
Firstly, quite a lot of Jews do speak up, but we're not generally quoted or given much profile by the media. Jews who are defending Israel's actions and saying they are so scared of antisemitism they want to move to Israel are considered more newsworthy.
Second - I think some Jews do want to criticise Israel, but it would mean literally all their friends and family stopping talking to them. Some of my friends and family disagree with me and DH criticising Israel and speaking up for Palestine, but are open minded enough not to refuse to talk to us on that account. Also most of our friends aren't Jewish, so we have a lot less to lose than people whose whole social circle is.
Third - Israel is not just some nice-to-have place to do Jew stuff, it's not important because 'God gave it to us' or it fulfils some prophecy. The point is that it is supposed to be a refuge for Jews after millennia of persecution, the one place we won't suffer for being Jewish. Now personally, I feel much safer in the UK than I would there, but I understand people's strength of feeling and if Israel ceased to exist as a Jewish state tomorrow, it would be naive to think that Jews everywhere would be just fine. So there's a lot of fear about 'what if something happens to Israel?' (not for me personally, but I understand others having it) and I think many Jews fall into a belief that 'No one else will defend Israel, so we must - it didn't do that, it can't have done that... or if it did that it must have had a reason'. There's this desperation to believe it couldn't have done the things it has.
Personally I think if we want to defend some sort of future for a Jewish state, we need to call it to account and be clear it can be called to account like any other country rather than defending it regardless of its actions.
Sorry, bit of a diversion, but needs to be said.