Disclaimer: I don't know anything about the trails in COS and have never ridden anywhere down there. That said, one of the first things mentioned in the article is that one of the steeper trails (Daniels Pass?) was remade into a "gentler, switchbacking trail to cater to people on foot and wheels". So my thought is that people are pissed for two reasons: one, they potentially took away a steep, fun descent. And two, yet another trail system is built without any legitimately difficult trails.
It's funny you look at it from the angle of modern bikes making trails easier, instead of being more progressive and looking at it from the other side. Why not make trails harder to accommodate for better bikes and more skilled riders? If you do that, you also give the beginner and intermediate riders something to work towards. Instead, almost all new trail systems have to be "ridden by everyone", and a significantly large proportion of fun/difficult trails are unsanctioned on the Front Range.
It's funny you look at it from the angle of modern bikes making trails easier, instead of being more progressive and looking at it from the other side. Why not make trails harder to accommodate for better bikes and more skilled riders? If you do that, you also give the beginner and intermediate riders something to work towards. Instead, almost all new trail systems have to be "ridden by everyone", and a significantly large proportion of fun/difficult trails are unsanctioned on the Front Range.