Looking through the naked gardening info on the web, I ran into the opposite.
http://www.diynetwork.com/made-and-remade/learn-it/world-naked-gardening-dayNo. 1 bugs will bite whether you got clothes on or not. Sure being naked does give them a bit more to work on, and something to get trapped under which can be an issue. Ever get a bee under yer shirt? Or ants in yer pants.
No. 2 is really irrelevant, don't think being naked makes us enough more vulnerable to sharp tools to be concerned about it. I even run a chainsaw naked, no big deal, I have to watch where that bar is anyway and be in complete control. But I suppose a person without my experience and physical skill and strength might be more vulnerable.
No. 3 Thorns are like to get ya no matter what ya wear. Might want some armor on if yer going to intentionally charge through a thorn thicket, but regular gardening I don't think it matters. I've even picked my way through a thorn thicket naked, get an occasional scratch but no big deal.
No. 4 Just get rid of poison ivy if ya got a problem. Spray it with vinegar. I'm not allergic to it so I just ignore it like any other weed.
No. 5 Spend more time in the garden naked and sunburn won't be an issue. And the extra Vit, D will help yer health.
No. 6 What in the world does leaning over have to do with discomfort while naked? If it's uncomfortable naked it will be just as much so clothed. (if not slightly more so) That one makes no sense whatsoever. I use knee pads when I have to kneel very much.
No. 7 Footwear is for foot work, wear it if needed, but the rest of ya can stay naked, that doesn't make naked gardening less inviting at all.
No. 8 gloves are for protecting the hands, use em when needed. Another one that's irrelevant.
No. 9 I use a straw hat to keep a cool head, or at least keep it from overheating quite as fast in the hot sun. Another irrelevant one.
If that's the best anyone can come up with against naked gardening. The arguments against it wouldn't hold up in court when balanced against the benefits.