In its strictest sense, the statement is correct.Much of the information found at these sites has been provided by ordinary researchers like you and me.There exists varrying degrees of accuracy, depending on how thorough the submitter has been in his/her own research.Any site that gives you a view of the actual documents is preferable to one that only provides information someone has submitted, most especially when the submitter refuses to divulge sources.
In my opinion, the message boards are great for making contact with others researching my surnames. These contacts have often had information, including documents, that they have been willing to share.Years ago, eight persons researching my primary surname "met" through the surname message boards at Genealogy and/or Rootsweb. A coalition evolved wherein we have continued to share our findings with each other.We more or less take turns ordering copies of original documents which we then share with the others of the group, and we have regular discussions about what these documents really mean.
At sites like Footnotes and some state libraries, one can view/print copies of actual documents.Footnote provides images of many NARA records and charges a nominal fee.Other sites, such as Rootsweb, used to have good clue infomation for which there was no charge; however, Rootsweb is now owned by Ancestry.While Rootsweb is still a free site, most of the documents that provided good clues have been moved to Ancestry, where there is a charge, so Rootsweb is now practically worthless in the clue department.
The bottom line is that, regardless of where the clue originates, you must prove it yourself.
If you get lucky enough to come across someone with a lot of documented information that is willing to share with you, never fail to say "thank you", and be sure to share to the extent you can share.
Done the right way, Genealogy is not a cheap hobby.Personally, I don't waste my money on subscriptions to any of the popular sites.I prefer to spend my money obtaining copies of the original handwritten documents.I do use the message boards.