Wrong. I have been working on and researching this topic for a long, long, while now. I find the entire realm of AMINO ACIDS very complex, huge and, at times, confusing. Whey and other animal proteins, plant based, casein, complete, incomplete, etc, etc…….We need protein to survive, for cellular metabolism, as well as carbs and fats.
You do have to find what works best for you, what works best in your diet and your wallet. Types of proteins. Great post on differentiating proteins. I avoid soy, this is a personal preference, because of the additional estrogen.
I just want to provide information. I am no dietitian or metabolic genius.
I love what whey can do for my muscles. I use Gnarly whey post workout, because it helps in re-feeding muscles post workout and can help with recovery (and does not contain artificial sweeteners). I try to avoid too much dairy, but whey is such a great source, it is almost silly to not take advantage of whey. More info on whey here. I use plant based proteins as well, but not for post workout, more to reach my macro goals in general.
It is a very personal decision, as well as a complicated one.
Hope this helps (or may make it more confusing) in choosing your protein!