I drink socially (read: 3-4 beers a week) and run 5km a day. I've never felt better. Extremism is not healthy in either direction.
Don't get me wrong: I drink socially and I'm fine with the occasional 'all-out' experiences, both for myself and others. Even if it is unhealthy.
But quitting alcohol entirely, aside from being a life-saving practice for some people, is in no way 'unhealthy'. So even if it is extreme (which I disagree with, many people don't drink at all), why would one consider this unhealthy?
It's not like he's going for an extreme carrots-only diet or something.