There has to be a balance between development and wilderness. People simultaneously want to live in nice houses, but don't want our forests cut down or mines digging up the ground for metals, cement, etc. Everyone has to give and take.
If you have evidence its primarily the cows dumping the e coli, then please post it. Otherwise, you're just speculating.
Sure, it's just speculation. I've never been to Wyoming, so cows and water there may be different than Louisiana. Chemistry and the laws of hydrology may not work the same way. There may be some unknown western fungi which hosts e.coli and has yet to be identified by science. Who knows, since it's all speculation.
While we're speculating, what do you think the chances are I've heard all these arguments before? If you had to speculate about the cause of high concentrations of e.coli in the water of Louisiana rivers and streams, would you speculate it was cows, or some other source?