Earlier quoted context omitted.
Read https://en.wikipedia.org/wiki/.coop Think about all of the organisational structures you know of. Then ask yourself how is a cooperative fundamentally untrustworthy?
My first-order heuristic is that legitimate websites tend to get one of the top TLDs (.com/.org, maybe .net/.io). In general, why should I trust domain_name.xyz over domain_name.com? There are obvious caveats, e.g. it doesn't matter as much for generic words like "gem" and for personal sites that I don't trust much in the first place. In this case, 3 seconds of critical thinking makes it clear that they have a plausi…
Of course, it's also true that many people won't have the spare time to find that out.