I think it does add to a bit of hysteria even if you are conscious of the fact that most posts will be one of the following:
1. Negative but legitimate i.e. top box failures
2. Negative but just whining, i.e. take your pick
3. Negative but only in the sense of someone trying to make the bike their own and comments on changes they would like to make
4. Positive but no need to keep going on about it, so very few
5. Negative and have no f...ing clue what they are talking about, i.e. again, take your pick.
Three extenuating factors:
1. From my experience with primarily sportbikes and sport tourers this level of negativity seems to only be prevalent on adventure tourers and the ilk. I've never seen it on Motorush, 600rr.net or any other dedicated sportbike site and I've been a member of.
2. When I was in the market for an adventure bike I narrowed it down to the 950 & the 12GS. Having used internet forums to good effect before regarding purchases I consulted Advrider. With the 950 having been out and the 12GS just released, most of the negativity fell onto the 950 ranging from points 1-5 above. Now fortunately I don't take the internet as gospel and use it only as a tool. But if someone was to take the internet as gospel then it might be an issue and result in an incorrect purchase. While I made the correct purchase for me and my needs I think if I was in the market now I'd be very wary of both models and it would be undue because if you really look @ the info and the posters involved, the legitimate complaints are few and far between. I can't speak for the 950 as much, but when you see the most negative posters regarding the 12GS, look @ their profile. Most consistently negative posters don't even own the bike. Pretty weak in my opinion.
The internet is only a tool. Use it properly and it's a benefit. But it's not gospel.