From the frontal pic further down the FB chain it seems like plain out lack of knowledge but who knows.
me neither
As mentioned, buy the Wells books and read carefully the introductions as well. They really do have all the techniques you actually need short of hardcore trails.
Then start from the green Wells trails, which range from dirt roads to trails that will seriously push most crossovers. Then get to moderate, blue trails. These often feature milder versions of what you will find on reasonable difficult trails as well.
Wells subdivides (look at the symbols) the difficult trails into such suitable for stock vehicles and such that he thinks are not. Of course, he is a bit conservative in that assessment but that is a good thing.
Remember that trails can change all the time. His CO books (2 for the state) are brand new and he has a new AZ book coming out early next year.
Yeah, the most popular trails everywhere have become a mess.
The Wells guides have all you need and he also sells GPX cards with the tracks. You will be on safer ground with Wells. Once you start asking random folks you will quickly drown in subjectivity: "Black Bear is kid's play!" "Black Bear is hardcore!" Wells guides are spot on for Wranglers and 4Runners (though harder to use with crossovers).
And join TrailDamage.com. For 12$ a year you get the most comprehensive guide for CO and southern UT with plenty of pictures of trails. And gpx files.