This supports both your view (average people) and mine (vested interest players).
There are a couple of reasons I hold to the vested interest argument. First, as I've mentioned, is that I have never encountered anyone in my everyday life who spontaneously writes to media about arbitrary topics. Never. Of course such people exist - it's just that I believe they are very rare birds.
Second, many years ago, I had my eyes opened a bit when a media publisher contacted me and asked if I would like to write a "spontaneous" letter to the editor commenting on a recent story. I was flattered and wrote something. After a bit of digging I discovered that all the other commenters had been solicited also. The games were much more innocent then than now, I think.
Unprovable issue either way. I wish we could get statements from those commenters and learn what makes them tick.
I'd still say it's just fear and jealousy as opposed to a vested interest. I think It's same with twitter trolls etc who get tracked down and arrested after saying something racist or threatening someone. Half of the time they won't be racist or have much of an interest in the person they got caught for attacking, but are essentially just losers who are angry at the world and need to fill their lives with something to make themselves feel better. I think the whole media-driven celebrity culture is a massive part of it. People just don't like it when others make money or become successful and they're jealous and hateful of it so attack it. This applies to both Bitcoin and celebs.
There was a recent case in the UK and you only have to look at the pair to see why they must be so angry, and reading further you see they obviously have other issues. The internet just gives a voice to the voiceless and for those to scared to do anything in real life. People only say stuff online because it's so easy to do and they think there's no consequences.