I'm Jewish and I don't think anything about this suggests the police are pro-protestors and anti Jews, I agree with Gideon Falter (the guy from the video) that it's more a result of the police being put in a difficult position. Sadly I also don't doubt we have already seen people going 'Oooh, bit of a coincidence eh that this guy who is chief exec of the Campaign Against Antisemitism decided to walk through the march' and assuming it was a publicity stunt.
I have attended a rally myself and felt safe but, as this video has shown, there will be some protestors who assume anyone Jewish not on the march must support Israel (and on the whole they would be right) and feel they are entitled to have a go. I do think there is a degree of glee among some of the left to feel they have a group (Zionist Jews) that it's 'OK' for them to be hateful to because hey, they're colonisers and therefore baddies. And that is not OK.
Yet I still dislike the idea of banning the marches - the best way for them to end, would be for Israel's bombardment to end, ideally with an exchange of remaining hostages and a peace plan, which would be nice if unlikely.