I let pretty much all manner of critter be. I'm not a hunter. I'm an interloper on their day to day and just happy to be allowed to observe them in their natural habitat scratching out their living as we all do.
Snakes, spiders, rats, any creepy crawly out there fascinates me more than terrifies me. As a youth, I used to go hunting for snakes. Not hunting-hunting, but it wouldn't be an odd thing for me to wrangle a king, garder, or even copperhead. I'd catch it, look at it a bit, then send it on it's way. The only snake I have ever killed in my whole life was a mercy kill. Poor devil found the wrong end of a weed eater, so I ended it quickly with a knife to his brain.
I will say, I have been charged by cotton mouths before. I was doing pool openings many moons ago and a wooded lot with a dilapidated pool was lousy with cotton mouths. It's the only job I ever turned away from for my safety. They were coming at me pretty fierce, and the pay wasn't good enough to fight snakes.
Copperheads can be aggressive as well. This past spring, my wife, aunt, daughter, and I bumped into one on the family property. It was cold-drunk and sluggish. It kept trying to decide if it wanted to run or fight. It would zip away a few feet the coil only to feign a strike and lazily race a few more feet. My wife had no idea what kind of snake it was. She's scared of all of them. I fibbed as said it was a garder. I just kept my boot between it and my daughter. Mr. Snake eventually went his way, and we went ours. Had he had his full wits and speed, I have no doubt he would have simply shot past us without a second look. The only times I have ever had issues with copperheads have been when they are cold and can't move as quickly as they would like.
My choice in woods revolver has to do with personal protection from two legged varmints and the very unlikely larger beast. A .357 will handle most anything I am apt to stumble across. Animals such as snakes and other less than cuddly critters get a full pass from me. I don't want to eat them, they don't want to bite me. The world would be poorer if I were to try and shoot or smoosh them. I would feel quite foolish having to shell out a sizable co-pay for anti-venom for bothering something that would head in the opposite direction if I give it enough breathing room.