Being against the monarchy isn't exactly anything novel or edgy, it's been the case since it's formation. The police fuck up a lot and the government's ambition to curtail peoples right to protest and strike is troubling; but its not like all protestors were dispersed or arrested so I suspect there's more to it. People have an agenda and this is great publicity for Republic- as is often the case the enlightened are also the most easily fooled.
I do think the balance is tricky, I mean realistically a few hundred protestors aren't going to halt the day or change anyones minds- the people who miss out are the 'ordinary' people who travel to see it. In this case they didn't cause disruption that would have affected others but perhaps this was due to the policing. A lot of protestors don't care about their fellow commoners anyway, just stop oil are deplorable and mostly hypocrites- Republic seem decent though.