What a non-sense comment, really.
We *ALL* can handle carrying around a 17" MBP if we wanted. It's not a matter of "capacity", it's a matter of convenience. And whether you like or not, the MBP is a 40% lighter, and thus more convenient to carry around in your bag.
It's more convenient than something that's already very convenient so the difference in 'portability' isn't a real-world issue unless you're a (word I can't say without being rude).