Under the Wilderness Act in the US, it breaks federal law to bring a motor into a designated wilderness. The idea is on protecting places where nature can actually be wild. Us humans getting to use them on foot ( or perhaps bike - though it's hard to maintain a bike trail without powered equipment) is a secondary benefit.
This land is only preserved from development because people are willing to pay taxes for the government to monitor and fence the land, and pay higher property values because there's less land for development.
If you want people to be OK with those costs, it really helps for them to be able to actually go and see the beautiful land that they are preserving. It's not reasonable to expect people to care about nature of you don't let them experience it.
Really we should designate more areas as wilderness. i.e. no machinery. Humans can still enjoy the land without roaring across them in 4x4s.