Years ago I did some volunteer work. A meeting was called and, with some effort, we got a large proportion of the volunteers to show up. Unfortunately both the meeting and its agenda were hijacked by a faction within the group intent on pushing a political line that was only really obliquely related to the actual work we were doing.
The result? At the next, far more important meeting, nobody showed up except the political crowd, and the entire organisation thereby fell into the hands of that faction, at the expense of the actual cause we were working for.
So your words are wise, o Crispy one. Plus it's a handy little trick to bear in mind if you are of a Macchiavelian disposition.
If nothing else the marches showed how many people dissented, and will have encouraged those few politicians with scruples to actually say something. A few even did.