Studies have also shown that calcium from plant based sources is poorer quality and harder to absorb, meaning vegans are more likely to be deficient in calcium than non-vegans. People can pick and choose studies to suit their argument, nutritional studies are notoriously biased and flawed.
Most of the major contributors to ill health are vegan such as alcohol, tobacco, sugar, salt and refined vegetable oils / syrups, these account for the majority of obesity, strokes, heart disease, cancer, diabetes...etc. The link between animal specific fat and heart disease has long been debunked whilst the links between meat and cancer are tenuous at best and even then only pose a similar risk to certain widespread pesticides used on vegetables.
A balanced diet high in unprocessed, natural foods is the answer, there's no reason to exclude anything for any reason other than personal preference.
Don't get me started on the hypocrisy involved in the compassion / environmental arguments!