I'm not quite sure how you're reading it, but what they mean is 'the reason to have different offsets is so that morning/sunrise happens circa 8am everywhere in

I'm not quite sure how you're reading it, but what they mean is 'the reason to have different offsets is so that morning/sunrise happens circa 8am everywhere in the world (in local times), but why is that a goal - why care if it's circa 8am or circa 9pm or anything else, it can be at different times in different places instead of them having different offsets to make it the same'. Note I'm not saying I agree, just explaining.