Pogue Mahone
Clarkson the Helicopter Dad.
It falls within the usual Vegan talking points of - Planet, Human, and compassion towards animals. A person can gravitate towards this sort of thing for any one of the three.
Yeah, the vegan philosophy makes a lot of sense. The logic is internally consistent. Much more so than people who won't eat meat because they say they don't want to be responsible for animals being killed, while still eating eggs and dairy products.