From what I could gather from the jumpy site, the protestors were mainly not anti-vaxxers. They were mainly made up of people who oppose compulsory vaccination passports. I include myself in this group(I am doubly vaccinated - so am not an anti-vaxxer). They are also against child vaccination. Here I simply don't know. We do not have enough data, so I would err on the side of caution were I a parent of an U16.
This does not make me a nutter - or many of the people there. I find it disturbing to say the least that the screaming label of 'anti-vaxxer lunatic' is being yelled out about people with genuine concerns.
That said, they do seem to be a bit of a disorganised crowd.