I was wondering in the video replays I watch when I see people doing the jungle they constantly hit the mob turn around to run then hit it again. Why do they keep taking a step back? As far as I can tell there is basically no way you can dodge the damage on something like the Red Brambelback. So why do they keep running from it? I see no benefit to it and just more chances for you to lose and auto attack.
If their attack speed is lower than the monster's, they want to back out of its range until they can attack again to minimize the amount of damage the monster is capable of doing.
Also, they may be repositioning the monster it to a safer spot, such as in a bush or nearer their escape route; they will probably do this and the above at the same time.
Lastly, moving around makes it harder to get hit. Even if no enemy is around that you can see, sometimes they have your position warded and might try to hit you while you kill the monster (if you're standing still it's pretty easy).
Ranged champions can move out of attack range and get a "free" attack off, so long as they don't move too far away. All champions can also move the camp closer to where they want to go next, so when it dies they can get where they're going a bit faster.
I think most people do it because they see high elo players do it. I believe the idea is that if your enemy had a ward on you and was just out of sight of you you'd be more likely to avoid a skillshot thrown by them if you're always moving. There could be additional reasons as well.
