Recreational vehicles have always concered me. Just turn on one of the Saturday morning fishing shows, all you see are grossly overpowered boats flying over the water at 40 mph. Just kicking up a damaging wake, and frightening every living thing within a mile, including any peaceful paddlers. People are unconscious worshipers of anything in excess. If you examine a lake with much boat activity, loons and other water birds tend to be scarce.
Another issue with recreational motoring is that it allows people without skill or respect for nature to get into places they would otherwise never bother to go. Sometimes they get stuck in bad situations requiring rescue. Generally if you can get somewhere under your own physical power you can also get out.
Regarding ATV's, I see them causing heavy damage. The mentality of most users has no respect for the natural world, except as a setting for ripping and roaring, the favourite activity being finding mud holes in trails, then making them worse in the hopes of taking turns getting stuck. Over time the trails become so damaged as to be impassable, then the drivers continually branch out causing greater damage. I feel this is unacceptable given that much of this occurs on public lands.
But in reality it's personal automobiles that account for nearly all vehicle environmental damage around the globe. Paving (ribbons of petroleum), and destruction of habitat for roads, and all the emissions and energy inputs to produce and run personal automobiles are a very heavy cost to the planet and mostly a needless waste of very valuable resources. Truth be told, much personal driving is discretionary and convenience or entertainment motivated. The trends of development of personal vehicle design seem to have far more to do with bragging rights and social measuring than practical need. We have built our entire society around the assumption of personal vehicles and near free energy to drive them.