Sadly the vegan crowd overlaps too much with the pseudoscientific new age/alt med/antivaxxers crowd, so skeptical types are quick to dismiss any suggestion that such a diet is healthier.

And people generally don’t like to hear that eating meat is bad for them anyway.

If anyone is interested in why you instinctively react so negatively to the idea that your diet is unhealthy and unnecessarily wasteful/harmful, there’s a great Ted Talk on it: https://youtube.com/watch?v=o0VrZPBskpg