Commissario
One of the main reasons that there are "facebook groups" with information on how to claim is because most claimants don't have a clue how to fill the very deliberately obtuse, confusing, misleading and frankly in breach of the law (as written) forms out.If anything it's ultimately causing more friction for the genuine claimants too - there are obvious feedback loops, people learn the ins and outs of the system, share how to exploit it, the government tries to address it... that places an admin burden on everyone and so it goes on...
Most of the big charities for various diseases have had guides on how to fill the form in based on the sorts of issues specific to that disease for at least 20 odd years, the Citizens advice bureau used to help people fill the forms in by basically sitting with them one to one and asking both the question on the form and real world examples of how that question impacts daily life and then if needed help with appeals, IIRC they had to stop doing that about 10 years ago because basically as it was becoming too much work for their resources given the governments push to effectively say no to everyone who applied.
I've said it before there are questions in the form that are very deliberate "gotchas" and things like questions where there are two answers that are according to every English dictionary synonyms but result in different "points" (I've mentioned it before, I passed one question i was looking at with a friend on to some of my other friends, even the lawyer couldn't understand why there were two identical meaning answers - the words didn't even mean something special in legal terms).
Many people will look at the questions on the form and say "yes I can do that", without remembering that legally the question isn't "can you do this", but "can you do this safely, as required and repeatedly", so a lot of people might answer very honestly but incompletely "I can do this", when the reality is under the legal definition the form is meant to go by the answer is "no" or at best "sometimes".
For example "can you wash your hair" sounds simple, until you realise it means "can you wash your hair whenever you need to" not "can you wash it at all", same with "can you lift a pot of tea" it's not "can you do it once a day" or "can you do it but risk seriously hurting yourself", or "can you lift a can of beans" means not just once but say at the minimum unloading shopping, or more likely doing it repeatedly over a fairly long period.
Then there are the questions where the claimant needs to be exceptionally honest with not just the PIP assessor, but themselves.
It's embarrassing for most people to admit that they might not be able to get washed every day, or might struggle to to handle their toilet needs, or remember to do really basic tasks.
The assessors will also take the generic polite "I'm doing ok" when they ask the routine sounding every day question "how are you" as meaning you're ok in the normal sense, not that you're "ok" for you, or "I've got conditioned to say this by society as people tend not to want to know the level of pain i'm in*, or that I'm struggling to remain upright".
The system for getting PIP is exceptionally hostile and deliberately made so that most people won't manage to fill the form in correctly without assistance.
*I know a few people who are at pretty much opposite ends of the spectrum on that reply, one will give you a full rundown of her health and pain levels at that moment in time if you ask the question and you're a friend, and one who basically won't admit she's about to go sideways onto the floor unless she really trusts you or she's actually going over.