The whole of the quotation in the title is "The price of freedom is eternal vigilance" and the many demonstrations that have been mounted recently have been by groups claiming their right to exercise "eternal vigilance" about events and attitudes that they see as threats to freedoms of one kind or another. Not allowing the marches would be against the policy of allowing peaceful demonstrations and free speech.
There may be a case, though, for keeping main thoroughfares open to prevent the marches from completely paralysing the lives of the rest of the community - that does tend to lose them public sympathy anyway.
On the other hand - would that inspire the demonstrators to break the rules and take the banned routes, hoping to prove the validity of their protest by the amount of disruption they can cause?
I think someone got out of the wrong side of the bed
Bereavement wipes out everything
A drop in the ocean in the great schemes of things....but replicated by how many more
