Scott, I agree with you......that wool is not a good barrier against bugs when compared to nylon.
However, this year when hiking in Colorado for over a month I treated all my clothese, including my long sleeve wool shorts with permethrin, and i did not get one bite. The bugs sometimes landed on me, but they bounced or "rolled off".
If I'm hiking for over a day polyester and other synthetics cause me problems in terms of comfort and stink. I just start feeling sticky and the fabric stops breathing or keeping me warm when I need the warmth because it feels sticky and it is not breathing well/ Whereas, my wool tops continued being comfortable without washing for a couple days.
I'm totally sold on wool and I've been slowly converting my winter and summer gear to wool. I first made the change with my winter gear (base layers).
However, the downside of wool is that the thin 150 weight ones are not that UV protective and I still like a nylon UPF protected button down shirt when I'm just sitting in the exposed sun for long periods.