Veganism is an emotional choice made by less than 1% of the population, yes you can be healthy on a vegan diet although I would question that a vegan diet is healthy for a growing child.
Vegans don't consume animal products, meat, milk, eggs, fish, wool, leather and several other items, it is easy to see that leaves a lot of gaps in nutrition. If individuals want to live that way it's fine by me, but there are no partial vegans you are or you aren't, it is fashionable to say you are vegan, but then you cheat.
The U.K has the strictest animal welfare and environmental standards on the planet, no country does it better, and 99% of us are content with that