It is a bit confusing - I;d like to see the research too - I dont think it is just a seminar as it is widespread... if anyone finds the researcgh pls post it...
My gut feeling is that a lot of MCHN's where never happy with the 6 month recommendation and as such will quickly jump to anything that does not support it. Also a lot of it is the "mummy grapevine", all it takes is one mum in one mothers group for the word to spread like wildfire. All it takes is one seed of doubt.