My only experience is at Crossness where I have done some voluntary ragwort pulling under the guidance of the reserve warden. I certainly wouldn't describe what goes on at Crossness as "hysteria" - the aim is very much control and not eradication. There is plenty of ragwort on the reserve which is left well alone and I'm very glad about that as it lets me get shots like this one...
But we also have areas that are grazed and, exactly as eeyore says, those areas need to be kept reasonably ragwort free or the tenants will, rightly or wrongly, move their horses elsewhere. So every year or two we clear any ragwort that has spread from the uncontrolled areas into the grazing areas.
Dave P.