Well, the original ban on motorized transport was because they didn't want roads, parking lots, etc. A heli, or a float trip down a river, are pretty non-intrusive.
Consider that those user groups may actually be your friends. Also, things like float trips (which some hardcore enviro types do want to see banned) are great vacations and a great way for people to actually experience more of the outdoors.
A pet peeve of mine on this point is motos. Yes, there are jerks, just as in any user group. But, responsible riders are no louder than a large hiking group, and a lot of moto trails are actually pretty buff single track (those trail degradation horror stories do exist, but they exist for hiking trails, too). They're certainly not as high-impact environmentally as horses.
I don't expect them to win being allowed to ride in wilderness areas any time soon, but for many other areas they're a group of users that people should be more open to including rather than trying to shut the door on them right after MTBs are inside the door.