Almost every food has protein.
Yes but some foods are easier to digest and assimilate than others...
And some plants parts can demineralize the body, read about phytic acid or oxalic acid.
Broccoli has more protein than steak, but it sucks eating it raw.
With the same training (running, jumping landing, lifting my body weight and external weights) i have felt and looked weaker on a plant only diet.
The reason i think is that either you spend all your day to go buy fresh green leaves and fresh fruits and you eat all the time (but this is probably not good to do that), or you eat grains, lentils, beans, potatoes, and in this case your digestive tube will be full of sticky starch.
Even if i agree that the industrial way of breeding animals is bad, (similar to slavery, mistreatment, torture), if you feel weaker and lose too much muscle mass even when training, something is going wrong.
I have watched some videos of vegan bodybuilders and they have the same problem that i have noticed when eating only plants (during more than one year) : only the parts of the body which are trained by lifting weights are growing/keeping muscle. But look at the neck, at the face, at the wrists, at the ankles, it is as if they are sucked from the inside. This is not good.
Chimpanzees get enough protein eating what they do.
yes but they eat larvaes, ants, eggs, small animals...
For good complete protein sources in plants, i suggest nettle leaf, chlorella, spirulina, if you are sure that the source is clean (low toxic substances in the soils/waters)
People can become very strong on fruit and greens.
And i bet the same person would be stronger by eating some animal muscle. One part of having strength seem to be the cleanliness of the body so that electricity and molecules can flow well (so avoid sticky foods like milk and high starch and maybe eggs ?), but another part seem to be the amount of muscle mass.
My experience with grains, lentils, beans, potatoes and others roots vegetables is that they are more sticky than "clean" animal muscle (if the animal ate what he was supposed to eat and lived in a clean environment...)
I know that this annoys religious vegans but i have been open minded and tried the vegan way for more than one year. And i can tell you that many plant foods are harmful if eaten in large quantities (those high in starches or high in fat or high in phytic acid or high in oxalic acid)