Earlier quoted context omitted.
As an analyst, something in me twitches involuntarily at your response. By people like this you mean redditors doing internet sleuthing? But redditors doing internet sleuthing could be anyone; from detectives, to judges, to professional analysts, to trolls, to pr firms, to fraudsters and framers. The evidence they use can be anything from high quality to low/ fraudulent. And then we have the fact that the alternative…
But redditors doing internet sleuthing could be anyone; from detectives, to judges, to professional analysts, to trolls, to pr firms, to fraudsters and framers. Am I out of line to thinking that at least some of the types of people listed in your hypothetical group of sleuths have some sense of professional ethics to not recklessly speculate on a public web community in terms of a manhunt as was the case in Boston?
Answering as a more seasoned, cynical person professional sense: that's way too simplified. Processes and standards for police, judges, officials etc, differ all over the world, as do professional ethics and culture. In practice there are various incentives and norms and "professional wiggle room for professional ethics". The police often release images of suspected persons or specific evidence precisely because they want the public to connect the dots and report their suspicions, knowing full well it results in false positive reports (and often withholding additional evidence for release). A doctor might not be allowed to euthanase, but they can prescribe high amounts of pain killers. A prosecuter might not go post on reddit, but they might act through a sock puppet or leak through the media. A defence may do the same. Corporations hire consultants and PR firms to give the illusion of justification and action at a distance. A judge would probably not comment on reddit (if not just because of the professions technical illiteracy), but the conditions of their appointment, their staff, political alignments, social circles, tenure, and professional ethics etc are far from uniform and sterile. All of the above are liable to cognitive, emotional and systematic failings and biases in addition, as well as the failings of their education and background: on a personal anecdote, I find judges and lawyers notoriously bad at reasoning that requires math or probability. In my experience also, those in power frequently strategically leak, work through proxies and associations to avoid the image of going against professional standards and save reputation.
additionally, in adhering to professional ethics, we don't necessarily approach the truth (which is presumably our goal), as following systematic cultures and professional ethics can lead to bias: as I pointed out, these official systems frequently come to the wrong conclusions as well, and going against the norms of professional standards can be used to silence critics, shun whistle blowers, and protect the general institution.
All this comes back to my original point: don't just believe something because it's posted in reddit. But don't discount it as being inherently inferior either.
Be skeptical, but be a skeptic of reddit and officeholders. Think critically. Learn to think and the process of thinking: it's not just natural, it needs to be learned and practiced. Learn the biases and common mistakes. Observe the evidence and the process used to come to the conclusion, and then make a judgement.