I'd be pretty certain FF companies do have people to post. Actually I'd think they'd be pretty stupid not to, and that's certainly not something I'd accuse them of.
Think about it: It's advertising reaching straight to the people they want it to reach-far more effective than a random billboard, and it's free.
What's more people look at an advert and are sceptical about claims when they know it's an advert. Random user123456 saying "my child had constant wind when I bf them, I changed to ff and they were immediately happier and slept through the night etc..." is far more likely to have an impact. People think "oh it's worth a try". They even pass it onto others in RL. "Someone I know said they changed from bf to ff and baby was immediately happier."
Also, as random user123456 they can make claims that are totally false without fear of being pulled up by the advertising standard. So User123456 says "ff means that their fine motor control develops quicker because they play with the bottle" or something totally random like that. But people read it think "oh I didn't know that" and again, pass it on as fact.
I don't think mn does discourage bfing. As others have said, anyone commenting they did it, or talking about the benefits is shouted on for making people feel bad about ff.
"Fed is best" falls through when someone posts that their friend/neighbour/mil is feeding the 6 week old baby rice doesn't it?
The thing with the bf/ff debate is that people do latch onto an excuse as to why they didn't breastfeed. But it's passed on. Person 1 says "oh I wanted to bf but I couldn't because my milk was too yellow*".
Then person 2 who's trying to bf but is not confident and worrying that they may be doing it wrong thinks "oh that's the problem, my milk is too" and they tell people too. So the excuse goes on, passed by mothers trying to be helpful.
(*Yes that was deliberately a rubbish excuse)
When my oldest was a baby you'd be amazed at the number of people whose "baby was allergic to bm"
If there genuinely had been that many people whose children were allergic to bm then the human race would have died out. 
Most people's reason was either the baby cried or they were sick-a fairly standard thing both ways. But I came across people saying it at toddler group, and finding the next week someone else had stopped trying because they thought "oh my baby's sick a lot too, must be the same" in some cases when breastfeeding had been going fairly well. But they were then scared that they might be causing their child damage by feeding them something that they're allergic to.
The thing about the benefits is in any individual person you cannot put anything down to them being or not breastfed. So it comes down to anecdotal evidence which is easily dismissed and can easily be used the other way.
On average the child who is breastfed has been shown to have fewer ear infections, fewer (or less severe) allergies, be more intelligent, less likely to have severe asthma, less likely to need SALT etc.
But on the individual side, ds was breastfed and he had constant ear infections from 10 weeks old and still suffers from his ears.
Dh was formula fed and has no allergies etc.
Dh's brothers both have an allergy to a common food product. #1 was formula fed and is very allergic. Tiny bit of it and he'll spend the next 24 hours bent over the toilet #2 was breastfed and gets minor tummy ache if he eats a lot.
Was this due to the way they were fed as babies? Something no one can tell. It could be, but equally well it could be just one of those things. As I said dh was ff and is not allergic at all.