Are you so naive as to think this was the first time a pork producer illegally disposed massive quantities of waste into public waterways? Do you think it was just some random coincidence that an activist group happened upon this pollution? Everybody who paid any attention to the problem already knew do this was going on regularly and on a massive scale. When you dump a river of pig blood into a public waterway you leave plenty of evidence. Neighbors have been trying for over a decade to stop this, but the authorities never listen to them. Pork producers just bullshit the public claiming, assault the science, and write checks behind the scenes to keep business as usual.
Yes, it was very much the case that public officials were actively trying to protect industrial pig farmers and they succeeded for years. If it wasn't for the activists galvanizing the public and shaming the government then nothing would have happened and everybody would still be drinking hormone-injected pig's blood.