There's a lot of health benefits when it comes to the plant based diet, but ultimately certain diets work for different people. One might do incredibly well with it and someone else might fail at it.
I tried to be plant based(hit every micronutrient/macronutrient) but I ended up with stomach issues so I went back to the generic omnivore diet.
Just had a blood test and my results are perfect so I'll continue to stick with my current diet.
Now, when it comes to moral ethics, that's a totally different story. I agree with their movement but it's hard to be apart of it without risking one's health.