Lots of people on Reddit were casually referring to people as suspects, notwithstanding the subreddit guidelines.

Salah was wearing a bright tracksuit that stuck out, and I think he's got a pretty memorable face -- I would bet a good amount that when a day or two passes by, what people will remember would be that he was one of the suspects. The association in their minds has already been made. And, there's a non-zero chance at that point that someone will misread the post, or recall it inaccurately, there's a chance that someone might attack him in an attempt to catch him or something. Public, vigilante justice is bad, full stop.

I've (reluctantly) edited the comment.

Perhaps reddit needs a NSFW-like roadblock for special cases like this: Before you can enter the subreddit, you need to acknowledge that everyone is presumed innocent, that reposting things elsewhere can severely harm innocent people, that vigilante justice is bad, etc. Click each checkbox, hit submit, and only then do you get to start reading and participating.

You're absolutely right about vigilante justice, but there's a big difference between that (i.e., playing judge, jury, and executioner) and public evidence-review assistance (i.e., playing forensic investigator).