Pound-for-pound snakes are wimps, & they know it. Even the poisonous ones generally eat prey much smaller than themselves.
I caught me a 6' gopher snake just last week on a hike, & as careful as I was to not break its bones (its a challenge to catch a wild snake that large & to NOT break some of its bones (they'll naturally put up a fight)), I still worried that I'd compromised its strength enough to badly jeopardize its life.
But I'm particularly ticked at myself cuz I carried him a distance to show him off to some friends but wasn't mindful enough to get him back to the exact place I'd gotten him from. And oftentimes that can mean the doom of the snake once the night sets in & the other critters all come out.
The last thing even a large rattlesnake wants to do is tangle with a human being. Even if it gets a bite in it knows it's almost sure to die from such an encounter.