To clarify a bit, the police made unreasonable demands for security because they didn't want it to happen at all. The 2 meter tall fence was an excuse to raise costs to make sure the organizers couldn't pay, and thus it will not take place.
They did not have any intention of having those fences, and didn't actually put them up when they were forced to secure a demonstration as per the law.
The police's ridiculous demands were one of the driving forces that caused 3000 people to come to the parade, even though it's a small city. Many people from far away made the commute to support, specifically because the police made those demands.
Even myself, a resident of the city, was unsure if I'd go. I'm not much of an activist. But the thing with the police forced me out the door, and if they would have denied security, I would have been there anyway, risk of being arrested and all.
Same here.