I'm one…hasher that is. Have founded a couple of hash groups over the 25 years I've been doing it as well.
It's harmless fun, and intended as a sociable form of running. In my experience it attracts people who might not otherwise consider running/walking, or in fact any form of exercise. It's set up to be deliberately non-competitive (all the false trails etc mean that everyone finishes at about the same time, but the faster folks have covered more ground).
The songs and drinking kinda reinforce this – it's also totally non-hierarchical, no-one cares whether you're a CEO, a Brain Surgeon or a Binman (we have all 3 on one of the groups I run with). The nicknames everyone receives also support this – everyone is brought down to the same level.
The social/after run bit is the most important. Most of my good pals I've met through hashing over the years.
It also works a bit as an informal 'international brotherhood'. I've pitched up in several strange cities and countries, have contacted the hash, and thus tapped directly into an instant social life and source of local info. In many cases, I've also been given a bed for the night and all sorts of other help.
We tout our group as running for people who don't like running. If you fancy it, see http://www.hhh.org.uk and find a local group.
If you want to be snotty and decide it's "jolly hockey sticks" then I guess that's up to you.
Littering?. I think you'll find that flour disappears after the first rain – hardly a toxic nuisance either. Some folks love criticising, don't they?.
Definately no worse than SS'ing 😆
Good video link up there by the way. Was shot in Embra and Glesga. I was the hare (trail layer) for the run where everyone is wearing red dresses 😀