The biggest factor of rattlesnake populations is how much prey is available. Well-fed females will readily breed and have much larger clutches, poorly fed animals may just perish.
I'd happily eat snake.
However, the entire 'roundup' phenomenon treats the animal inhumanely.
I eat meat. I kill wild animals and eat them as well.
However, I don't capture the animals I harvest and, prior to dispatching them, put them on display in terrible living conditions for others to gawk at as I put on a show.
I have zero issue with hunting snakes. I have zero issue with responsible population management if harvesting some animals will IMPROVE an ecosystem.
However, the 'rattlesnake roundups' are done for serious profit. Any negative impact on species populations is going to be ignored as long as money is being made.