Yes, yes, but where does all this posturing come from?
I'm thinking about Lynda Barry's cartoon strip, 'Two Questions', in which her cartoonist persona, hard at the creative act, reminisces fondly about how easy it used to be to create, to enter into the creative flow and enjoy it. And then two questions begin to take over: "Is this good?" and, "Does this suck?"
Barry can't answer these questions. They are unanswerable and eventually she gives up admitting she doesn't know. But this is the point: "To be able to stand not knowing long enough to let something alive take shape! Without the two questions, so much is possible. To all the kids who quit drawing... come back!"
Ideology is an adult club. It means: 'We believe we have the answer to what sucks and what's good." The two camps, by deduction, are full of people who have (temporarily?) forgotten the joy of creating poetry. When you've got it, you're doing it, but when you're hung up on the questions of what constitutes good or bad poetry, you're often flailing away in private, producing nothing of merit. The response of many to this is flailing about in public, representing principles of artistic value (not, I stress, 'worth', as the imposition of ideology on creativity is clearly a commodification of the unquantifiable) that are indefensible, but give a sense of community through tribalism.
The hollowness of these values are what probably makes most people despair - readers and the more benign writers of poetry as well. Announcing an artistic manifesto - as the Vorticists prove - is a call to arms as well a way of raising the defenses around a tribe. The media, also, like a good ruck, so they will often latch on, in a minor fashion where poetry is concerned, favouring whichever side is willing to make a bigger fool of themselves in their pages. The extension of this kind of tribalism, through various modes, conceits and also stabilisation within mainstream bastions, is probably worth investigating through the window of anthropological study, as I'm sure it comes in cycles which stack upon the correct traditional Hanoi towers with minor progressive inflections.
But ultimately, "an investigation of the nature and meaning of poetry" when it's based on analysing these self-appointed hierophants (they've been 'vaticinised' like in that godawful opening line of Sean O'Brien's 'Drains' poem), is going to end up biting its own tail because of the inherent emptiness of ideology.
What is interesting is that postmodernist experimentation has managed to parody these ideological movements in order to recapture the childish joy of creativity. For example, the 'Infernokrusher' movement, ("Explosion is the new transgression. Demolition is the new deconstruction") is a context for generating art, rather than a serious group, just as Oulipo isn't really a movement - it's a process for creating work.
 See Lewis Hyde's The Gift for more detail (yes, I'm a convert, it's a form of ideology for agnostics), or if you're lazy, the opening lines of Robert Graves' The White Goddess, where he describes poetry as having no yardstick by which it can be measured.
 When I say mainstream here, I mean ideologies that are accepted widely within marginalised groups as well - for example, the JH Prynne camp is a form of mainstream within the avant garde, despite having only a handful of acolytes within its boundaries and those being of greatly varying styles.