With that rather graphic account, I imagine people dressing up in full bio-chemical protective suits, complete with breather masks looking like Vorlon encounter suits.
Maybe a little like the girl from Blair Witch Project whining about how hungry she is while filming wild edible plants? Why didn't she look at that survival guide she brought at least ONCE? Not even a simple "Hey, I'm really hungry, maybe this book will have something listed in it I can eat?" Can you tell that movie annoyed me? It made people scared of a place I call home, when I know full well that if you prepare yourself with some knowledge and skills beforehand, you'll be fine and really enjoy yourself.
So, sure, coat yourself in goop from the store, dress yourself up in your shin-high boots, wear several layers of pants (all tucked in), and several long sleeve shirts, thick gloves and a mask. You'll be protected from poison ivy, snake bites, spiders, (not mosquitoes; they always manage *somehow*), prickly grass seed pods on the beach, lady bugs, sunlight, and maple trees. But you'll also be miserable. Sticky, probably too hot, unable to move about freely, unable to move silently (you'll scare off any chance of seeing any wildlife this way), and the birds will shout their laughing calls for miles, as they try to hold onto the branch tightly enough that they won't fall off from laughing so hard.
If you are actually clearing brush that has poison ivy, however, wear appropriate clothing, and remember that the resin will be on your clothing and shoes as you strip down for your shower. DO NOT BURN POISON IVY! Even if you are wearing a mask, your neighbors won't be! Poison ivy in your lungs is followed by a trip to the hospital. You might add to your armour a bottle of Ivy Shield, an organoclay that will help protect your skin.
If you are just going for a hike in the woods, dress for the weather. I tend to wear as little as the weather allows for warmth and shoes only when I have to. I'm not scared of poison ivy. I know what it looks like and I'm unlikely to *accidentally* get into it or even brush it. Yes, a rash of poison ivy itches. It's survivable. It will not be a nuisance for more than a couple of weeks. The possibility of a little bit of itching compared to the freedom to enjoy life to its fullest is really no comparison at all.
So according to me, the number one natural remedy is Awareness. Know what it looks like and notice it. It's fairly easy to avoid on the afternoon outing.
What if you do have to go through poison ivy? In the summer, along streambeds, you can find touch-me-nots (also known as jewelweed). The stems and leaves can be crushed and smeared directly onto the location where you brushed the poison ivy to neutralize it. Pale touch-me-nots work better than spotted-touch-me-nots. Get yourself a plant identification book and go learn how to find these. They work really well to negate the itching for mosquito bites too. Your skin really won't look like a troll afterwards.
An important rule of thumb for ANY plant collection: Always leave untouched the first one you find as a dedication to whatever god you believe in or don't believe in, for gratitude. And *never* exhaust a supply of a type of plant in its natural environment. Don't kill the plant unless you have to. Both of these help to ensure that the plant will be available *next* time too. And don't kill the things listed in your guide as endangered, either.