You seem defensive, as if my post somehow challenged or contradicted what you've written, which isn't the case at all. I wasn't directing anything toward you, but simply giving feedback to the OP in a thread that seems to have mostly become a discussion of... milk.
Your posts above were intelligent, and I agree with them. I was actually going to quote you as well in my original reply when you wrote:
"If you just want to be in good shape and look muscular a vegan diet is fine." Protein and amino acids are more concentrated and available in meat, which would take more care and planning (and likely supplementation) for those on a plant-based diet to get the ideal amounts for optimal muscle growth, especially for those putting their bodies through the demands of elite-level strength training programs. The OP obviously isn't at that level, though, considering that he was asking for advice here on a tennis forum, so provided that he's eating a nutritious diet that meets his body's needs, I doubt that his diet is holding back his performance in the gym.
On a side note, what's your opinion on soy vs. whey protein powder?