I don't know how to say this without sounding like a condescending bastard, but really, did you take up Biology in your school?
I mean, it's basic knowledge that it's not just the protein that's important, but rather their amino acid profile (as in, how many of the 20 amino acids they contain and in what measure) and their bioavailability!!
Plant proteins are notorious for being deficient in multiple amino acids (the most prominent being Methionine, which is essential for muscle gain). Heck, plant foods are classified as incomplete proteins for this very reason.
Animal-sourced proteins, on the other hand, are rich in all 20 amino acids, making them the superior source of protein by far for building up your strength and muscle mass.
Watch this:
and this: