Chickpea flour is ground up chickpeas, the starch part and the protein part together. The recipe here cooks the chickpea flour until, like polenta, it thickens into a solid that can be used like tofu.
Making soybean tofu is a bit like making
dairy cheese, a coagulant is added to heated soy
milk that makes the protein clump together. It looks like cottage cheese at that stage. Then it's strained and pressed. Very different process.
I just checked - the protein levels in both are much the same, but tofu has fewer carbs.
I've never tried making chickpea tofu, but I'm thinking it would probably need to be cooked longer to get a firmer result. Polenta can be cooked very firm! Or pressing it would probably work, too.