Probably the people who oversee the compilers afraid of pressure from further up.
They have people who check all the media for mentions of races/horses and if one gets a prominent mention they cut it to avoid taking any blame for a potential loss.
They will also have a list of who/what has the most influence on the markets and adjust anything they mention.
As an aside, I've long believed that the influence of Pricewise is based on genuine information coming into the RP offices. It's the individual holding the title 'Pricewise' (currently and probably the longest-serving Tom Segal) interpreting the info, I think, that lends it its reputation.
For example, I think James Willoughby was the original. Now, I like Willoughby. He thinks differently. But he didn't last long as Pricewise after a good start. Maybe that was because he thinks differently. Then there was Mark Coton who was very successful and packed it in to become a premium-rate phone tipster. That venture seemed to bomb and he went back to the RP with his tail between his legs. Nothing much is heard from him now. I'm presuming he lost out on his 'sources' when he quite the RP.
Segal is very influential, as is Paul Kealy. Again, I'm presuming their strengths are in filtering the info coming in to the offices but I find my own selections tend to coincide more with Kealy than with any other 'tipster'.
The market is also very quick to react to Weaver and Blake, probably for good reason. They seem to get good information which they're prepared to pass on but only at the last minute. I presume they ask for permission to say they fancy something they've had information about if they mention it on the early programmes.
I also think the ITV team get good info coming in, enabling them to interview owners etc just before a race when the horse just happens to go on and win.
I recall going to Ayr one day with an ex-forumite from back in the C4 days. He had some kind of pass and the first person we met was the CoC. My companion asked straight out if there was anything we should pay attention to and two horses were mentioned, neither favourite for their respective race, and both won so clearly information had been shared.
I had a day at Hamilton with the same person and the same thing happened only it was just the one horse on that occasion.
Sorry for the ramble but it's early and I'm just killing time between my breakfast fruit and Weetabix...