6% of proteins in human mother's milk

[Parsifal]

One argument of the vegans/fruitarians against too much proteins is that there is only 6% of proteins in the milk of the mother and that it is the time where we grow the most and faster in our life and at the end of the lactation that amount drops to something like 3%.

80g of proteins is like 240 kcal so more that 10% of proteins on a total calories amount of 2000kcal.
Would it be problematic to eat as much proteins (because we would get a lot of tryptophan, methionine, cysteine and carnitine?).