http://wwf.panda.org/what_we_do/footprint/agriculture/soy/co...
I'm not even sure if you've read the source you've given as it states the same.
Not to mention that most soy humans consume is non-GMO (which excludes practically everything from Argentina and Brazil), and that soy is grown in China, and for example in suprisingly large quantities in Serbia. So it's not even necessary to cut rainforests.
What goes to feeding animals is mostly what remains after extracting the (more expensive) products destined to human consumption.
Besides, Brazilian animal agriculture does not use much soy. It would even shrink in area if it started using more.
I mean, you literally linked to an article that says
>Therefore, most of the world’s soybeans are consumed indirectly by humans through products like meat (chicken, pork and beef), dairy, eggs and farmed fish. People also directly consume soybeans in tofu, soy sauce, meat substitutes and other soy products... Limiting consumption of animal-based food products, particularly meat, is one thing people can do to help end this devastating trend.
to advocate for not switching to a plant based alternative.