"It's too hard" includes "It's too hard to just magically change the environmental factors making it difficult for this specific person". We can't just magically move every obese person to NYC, and unwalkable car-dependent infrastructure cannot be fixed overnight either, even if the people living there all decided to vote for politicians who would legitimately work towards making that happen (still seems unlikely). Unless and until we work towards fixing the societal problems that created the obesity crisis in the first place, we still need short term solutions for the next couple decades at least.