I think extrapolating from poor US environmental regulations to say that no where in the world is it sensible to produce dairy or beef is a bit of a false equivalence. We also don’t have lead pollution in our water, but saying no one should drink tap water because it has lead in it in a certain part of the US is also silly.
I’m all for alternative protein sources and sustainable agriculture, but eliminating meat consumption likely isn’t the best approach. The US, Brazil, and a bunch of other countries using stupid practices like slash and burn agriculture really need to develop and enforce more sustainable practices via regulations and enforcement.