We've all seen it, parts of trails where those with a lack of regard for both their limited skillset and proper trail etiquette have dumbed-down a singletrack into either a braided mess, or twelve foot wide abomination that even a novice ATVer could traverse with ease. One may classify this as trail sanitization, as it most certainly is, however I feel that this is far more prevalent than the misguided work of foolish individuals who tear rocks out of a slightly (or highly) technical section trail bed to suit their own lack of abilities.
Why this form of trail destruction is more prevalent would be that it takes much less effort, in fact it's most often as simple as not heeding to the basic trail etiquette tenet, "Control Your Bicycle". Those who actually control their bicycles on a singletrack stay in the tread, taking care ("care" being key) to not cut corners, blow turns, or braid the trail from the originally designed trail bed. The Dumb Downers are a horribly narcissistic lot and their misguided deeds destroy public trail resources seemingly everywhere.
The motivations of the Dumb Downers are most likely very broad, however ego appears to be the main cause. Egotistical individuals don't like to admit they lack skill, etiquette or fitness, amongst other qualities that responsible trail users often possess. One of the most common old school rules of the trail is, "If you can't ride it, walk it.". The fragile ego of a Dumb Downer is unable to accept this age-old rule and thus will modify the trail to suit themselves, with zero regard for the public lands they are denigrating. In the case of ego-driven Appholes in this light, one person may have the (dis)ability to turn a singletrack into a truck trail width route through repetitive abuses, just to feed their ego and attain the joke status of "legend" or some other bullshit level of Appholiness. Pathetic
The moral of the story here (as it appears everywhere in the MTB realm) is to respect our public lands and if you don't, find another hobby. The true enthusiasts begin with respect for themselves, their (RL, not some internet garbage-bin) community, and the facilities we all are supposed to share. Remember, just because you can't navigate a portion of trail, it doesn't mean that others lack that ability. If you are a Dumb Downer, please heed the first sentence of this paragraph, or toss ego aside and LEARN. Though I've participated in an MTB lifestyle for several decades now, I refuse to stop learning and seek out trails that probably frighten egotists because pushing my bike up what I may not be able to ride cleanly today is a place where tomorrow may be the day my desire to learn gives it what for.
Riders Come and Go, Kooks Accumulate