Zenpash... we (viewers) assume that you are aware of the potentially damaging business repercussions to the operation concerned, caused through posting a damning report on a forum that will inevitably become a 'Google Page 1' search response.
In that respect, it is entirely fair that people seek to establish credibility to public claims and question any specifics that seem vague and/or implausible. That doesn't necessarily mean they doubt the poster - it just means that people are aware that there are normally 'two-sides to every story' and that malicious reports, with the intent to 'punish', do occur online. Differentiating between a malicious report and a genuine, substantiated grievance or warning is only prudent and responsible. In doing so, those commentators are not expressing bias... in fact, they are trying to establish a fair and unbiased account of the actual events and issues.
In my personal opinion, where such complaints/reports are posted, the intent is often to damage the business concerned. Not always, but often. That is a weak motive for posting.
Where a genuine concern exists to 'protect' other divers, then an effort is normally made to raise the target business' awareness of the negative feedback given. Attempts are also made to raise the issue directly with the business concerned, before a 'public outing' is resorted to.
This process, generally, provides the business with valuable feedback - in an environment that they cannot dismiss - that helps encourage them towards positive change. You cannot control how the business will respond to such a report - but the manner in which they address it will often provide more than enough evidence for other divers to make a reflective decision about their operation, attitude and approach.
Likewise, the way in which a complaint responds to feedback, questions or critique also paints a picture in readers' minds. A defensive or emotional stance rarely succeeds in convincing viewers that their motives for posting are unbiased, benign or 'entirely in the public interest'.