See, here is where I would immediately be skeptical about the article:
enzymes that make the digestion of protein incredibly difficult
Enzymes are protein structures and are therefore very susceptible to heat. (I.e. when you would cook an egg and it turns "white" this is proteins beeing degenerated by heat)
You would NEVER eat raw soy (or other legumes thereof). They should always get cooked thoroughly. And in tofu production, you would also cook the soy milk in the process.
I'm not 100% knowledgeable about these specific proteins, but it sounds like big strawman to me from the getgo.
I had the genuine question asked once about "But lions do eat meat and how would you stop them?" In a discussion about why I am vegan. ๐