"discriminating" is not in itself unlawful. There's a small list of things you can't discriminate for.

Unhealthy lifestyles like smoking or tabs instead of spaces isn't on that list.

Not sure how I feel about this. It does feel quite wrong. But it also has a practical, logical side to it. Ignore being human for a moment: smoking is proven to weaken physical ability. Why do I want to hitch my wagon to a team that's slowly crippling itself?