They have no valid credentials other than having been on the Internet a long time and having an interest in researching urban legends as laymen. One of the founders, David Mikkelson, couldn't answer questions about fact-checking due to legal issues[1].

If you really want to play the "HN says the names of logical fallacies" game, then I'll do you one better and say that challenging me to refute every single line item is an appeal to authority and we should just trust them because everyone says we should. There's no reason to believe them any more than there's a reason to believe much of anything published on somebody's personal website.

[1] https://www.forbes.com/sites/kalevleetaru/2016/12/22/the-dai...