Wikipedia:Articles for deletion/Fringe science organizations
There is no doubt that these organizations exist.  It only took me a few minutes, for example, to find several articles in major newspapers (The Guardian, New York Times) about the Flat Earth Society.  The problem is not that the organizations aren't notable, it's that finding  supporting the categorization as ''fringe'' is not easy.  Such  sources do exist, but the effort needs to be put into finding them and being careful to not say more here than is supported by the sources.  For example, I found a http://timesmachine.nytimes.com/timesmachine/1979/02/26/111076648.html?pageNumber=14 New York Times article about the Flat Earth Society.  It says
— NONE, NONE
Stance: keep
Cited policy: WP:RS (Wikipedia:Reliable sources)