As someone who does perform poetry, I fully agree with this. When I compete in poetry slams, sometimes I do well and almost win the slam and other times I finish in dead last with low scores. Why? Well counts as good in slams in totally determined by what is common in slam poetry and what the audience wants. A typical slam audience is pretty much young liberal millennials of all races and looks . Either sad emotional poems, social justice issue poems or racial poems that uses the slam language works well with these type of audience. The thing about me is that I don't do those type of poems well. I do a lot of funny weird satire poems that tired to stray from the typical slam language.
When I look at performances of my poetry and see others in action, I don't think I'm that far away in terms of performances. People have told me they really liked the energy I bring to slams and how it made them laugh a lot. But the main thing about me is I'm not the typical that the "insiders" like. Even before I enter a venue to compete, there's a decent chance that it's already determined that the insiders or the audience want something emotional or racial to hang on to whether they want to admit it or not. Why? Well, everyone in these scenes no matter where they are from want the same type of thing when it comes to poetry. I went to The National Poetry Slam last August and it didn't matter where people were from, they pretty much wanted to see the same type of poems. The same type of poems outsiders wouldn't get or relate to. It was kinda like you had to be in to get these types of poems.
Those type of poems that regularly show up on Button Poetry's Youtube page are the ones that make big year after year. There is a lot of "fuck you, because we said so" in slam even if they don't actually say it to your face. You can't really be big even when you go outside of the box, there is a formula that wins slams and there is a formula for poetry in general on what people interested in poetry want to hear. It's never about the outsiders, it's always the insiders.