It was Remembrance weekend.
It wasn't about minimising disruption, at least for me, it was about staging a political protest, i.e trying to put pressure on the UK government to change its stance on calling for a full ceasefire in Gaza, on this particular weekend. Albeit a legitimate protest for many people in the UK, also for many people in the UK the Remembrance weekend is a special/honoured time and for many of such people political protest and remembrance should not be mixed.
It was obvious that certain parties would drum up tensions and that would bring various 'Numpty's' on to the streets, and that most likely it would be the Saturday. If the organiser's could not have anticipated this then that is unfortunate, presumably the Police did.
Michele Obama was once quoted as saying "when the opposition goes low, you go high", this in my opinion was a chance to win more hearts and minds in the UK by 'going high' and thereby, either postponing the march until the following weekend, or by calling for it the protest' to become a silent vigil, with no political banners or the shouting slogans in respect for the nature of the weekend in the minds of the public.
Have no idea how many children die in Palestine per day... one per day would be one too many!