OP I do know the type of mum you're talking about. I had a look at that Alpha Parent FB page yesterday, and one of my facebook friends is a member. She is very shallow and easily led IMO, and has a poor understanding of science IMO. She is exactly the type you're thinking of I suspect. She eats only raw food, is into loads of really hokey-sounding "healing" practices, doesn't vaccinate her DD, and last time I saw her she told me she refused any kind of scanning or tests while pregnant. I was about to ask her why, but then thought "do you know what, I really don't want to know, it'll only make me cross and won't change her mind". She also happened to BF for ages.
However although I recognise the stereotype, I think you are being very unfair by thinking that those who quote the WHO guidelines are that type! Personally I often quote the WHO wrt BF, when feeling challenged about BFing. I fed DS till he was 4 and am currently EBF baby DD. All their jabs are up to date.
Many people, like me try to follow the official guidance on safely. Where I deviate from it, I can explain why I think my individual circumstances are different from the studies involved, or why I am happy to take a specific risk.
On the other hand, I think many people have a poor grasp of science. Anyone who thinks Natural News is a good source for example. It's this kind of person who would have no trouble quoting the WHO on one thing and not another.
I think it's a bit bizarre though that you would think that anyone who quotes the WHO would be anti-vac, why would you think that? 