Unless you are deep, deep, deep into the backwoods, use the latrines. No civilized person craps on the ground in areas where other people will follow when there are more hygenic options available. Have a little respect for the other people who will come behind you. I've been in the field where people thought, "I'll just squat here" and it's disgusting. You aren't the only bear in the woods.
Party pooper.
I guess I'm one of your 90% who don't belong ... but I sure did enjoy my one-week auto tour of national parks and battlefields in South Dakota, Montana and Wyoming last month. It was a once in a lifetime trip to see national treasures, squeezed into 7 days of annual leave. I did some day-hiking with the family, but we didn't have time to make the 3000 mile loop by foot.
I didn't look for any tourist-traps (and I didn't see any INSIDE any of the parks), but the roads, restaurants, general stores, gas-stations and cabins in Yellowstone made the trip practical. (And I don't mind user fees for the parks. Other taxpayers who don't use the park don't need to fund my holiday).
Yellowstone is roughly 54 x 63 miles in size (3472 sq miles). "Put up a few dirt parking around the perimeter and make people hike in" .... except that only a handful of people would ever see it! Even though you "take it serious" (sic) when you visit a park, it's possible that even a he-man woodsman like yourself might not have a few months to dedicate to exploring Yellowstone.
I actually think the NPS does a pretty good job of both making our parklands accessible and preserving them (so that's there's something to see when you get there). You can stick to the main roads, or you can take off down little-used trails. But for goodness' sake, follow the rules and use the latrines when they're available.
Anyway, I have no problem with some access roads going through the larger parks. What I do have a problem with is building the kind of rest area facilities you see on the interstates, complete with fast food, souvenier shops and the like. I think if you are going to visit a national park, you should come prepared to rough it and leave civilization behind for a while. For me, that's what it's all about.