I think the rather important point here is that many parents frequent this site, who are not armed with any prior information and need help.
Therefore, to dismiss or even belittle recommendations from WHO out of hand because you have decided differently whats best for you baby, is irresponsible, IMO.
Thats not to say you are a bad parent for weaning early, feeding baby jar food (which i do use here and there myself), etc, you have just made your own choice.
It does NOT mean that because the government do not have this at the top of their list of things to change, and because C & G and other companies carry on labelling the way they do, that the WHO do not know what they are talking about, or exaggerate their research/results. Why on earth would they?
I think people should try to follow the guidelines given by the WHO and make sure that when people ask advice that they pass these guidelines on to those who dont know better. Better to err on the side of caution isnt it? I dont believe the statement "it never did me/mine any harm" is ever particularly sound advice anyway.
If early weaning didnt do any harm, id be interested to see literature or research on the increased incidence of bowel disorders such as IBS, Diverticulosis, Crohns Disease etc, and the increase in various food allergies/intolerances that are so much more common these days.