I don’t support their behaviour but I don’t think you are one to judge if they are/are not losing the plot.
I've come across a few of the organisers of this stuff by association with friends. The leadership group spread completely fabricated material about the government wanting to murder its population and using vaccines to control us, etc etc wild conspiracy stuff. Lots of anecdotal evidence of "I knew xx who died of xx and they had xx vaccine". Then the old mental health thing that the government is not telling the truth about suicides and business failures. It's basically cult mentality where they all just listen to one guy overall and spread their message. With of course a few tag-a-longs with their families to fill out numbers. Thing to look out for, if all your information is being fed by one individual or small group leading you all, you might just be in a cult.
There are of course a few lost individuals in the group that feel genuinely about this.
The feel in my community (in Melbourne) is that they would have all these protesters jailed if they could.
I spent a lot of time undoing the rot with family and friends that have fallen for their stuff, thankfully they are coming round to vaccinate soon.