I guess everyones experiences with snakes are different. Like I said, I have never had a snake strike out at me with no reason. Sure if I mess with them or torment them in some way they become agressive but they always try to get away as soon as I quit trying to pick them up and were usually trying to back their way out of the bad situation they were in the entire time.
My brother stepped on a cotton mouth once and it reached around and bit his rubber boot. As soon as he got off the snake it ran the other way.
I guess if I had a copperhead in a pop up with me I would expect it to be agressive too.
My suggestion is just get a good pair of snake proof boots. But I have found that good rubber boots are very effective at stopping very large cottonmouth bites as well.