Why do people, including furniture designer-makers, join associations?
Now there is a really interesting topic of psycho-social speculation.
To be brief: why do people join (or in the case of furniture designer-makers, why were they so exercised about having a newer better association instead of just getting on and doing the things themselves in ad hoc groups)?
They join because they see themselves as the sort of people who ought to belong to that sort of association - and vice versa. It's ideas in their minds in each direction.
It's a question of identity, and the association becomes a small (usually) part of their identity. But of course they're not in control: other people form part of this thing that is part of them, and they have different ideas and modes of behaviour. Therein lies the explanation of why people not infrequently behave so badly in associations - behaviour they would feel inhibited from indulging in individual encounters. They impugn people's motives; they object over strongly to other people's actions or even discourse; they misrepresent others' words and deeds; they hope to expel them. But they have to do so because they are correcting a wayward part of themselves. They don't mean to accuse others. It's a mild form of derangement, probably with a name in the literature (I expect it's the 'Strangelove syndrome' - remember his arm?).
These are the stronger (or madder) members. The more vulnerable join because they hope they are, or hope they will by joining become, the sort of people who ought to belong. They keep quiet and nurse their discontents. For the time being.
There it is in a nutshell, totally theoretical of course. No reference to any living person is intended or should be inferred, and no animals were harmed in the production of this post.