I'm just trying to imagine the outcry if cyclists were banned from using roads for a day! Or runners for that matter
Probably none.
Runners, cyclists etc are drivers too and (like most reasonable) manage to understand that sometimes there are events that are of interest to some people but not to others and sometimes that's inconvenient.
In my experience, the only people I find who get very het up or angry to the point of frothing about road tax and so on are people who drive only and like to whine about cyclists/runners at any given occasion.
Funnily enough, the same people I know offline who joked recently about running over cyclists as part of a rolling road block through the main town road (complete with lots of swearing and cheerleading from their equally dim friends), seem to lose all their objections to the same road being closed for local food festivals, music events, fair rides and other social events that involve drinking and socialising. In fact, they're often there, taking their photos without any thought for residents nearby.
They're the types who whine about a regional 10k running race closing some roads (with marshalls waving residents through during breaks in the crowd), but doesn't think anything of travelling to another local city for Big Weekend and the multi day road blocks associated with it.
There's something about any mass participation sport event that brings out the irrationally angry in a way that any other mass event doesn't.