The article at part reads like the vague "get off my lawn" ramblings of a bitter elderly man. Good luck attracting top young talent with this attitude.
Another important point is that most startups aren't a good place to stay long term, simply because (duh!) most of them do not succeed. Curious, isn't it?
Statistically, over a 3-4 year period, your startup is 90%+ likely to fail. Why would the best and the brightest stay in a failing project? The captain may be expected to sink with the ship (he often doesn't, and especially his first officers don't), but when you realize that this isn't your company, your "stock" isn't going to be worth a nickel since any meager sale profit will go to the series A investors, and if you don't start sending out resume you're going to be fired in a couple of months - why again are you expected to stay?
Also, many of the best engineers I've known have periods where they changed jobs, and then periods where they stayed at the same job for 2-3+ years. That just makes sense. If you can get hired anywhere, and since you can't really gauge the merit of a company from a few hours of visiting it pre-hire, you're likely to shop around and try to find a place that you like.
Ultimately, as you correctly pointed out, if an employee is truly happy in his current position, s/he will not leave. And it's your job as employer is to keep the employees you want happy and productive in your company (what other task does a manager have, really?). How anyone can ignore this simple fact is beyond my grasp.
Startups have some dreadful lows, so I can understand not wanting to hire people who will leave at the first painful moment, especially because one departure can trigger a fatal exodus. There are also people who just collapse during painful periods and a startup can't afford to have them... but the ones who collapse tend to have a certain passivity about them that makes them incapable of being voluntary job hoppers.
However, we're talking about entirely different sets of motivations when we compare the "stay-or-go" decision at a big company vs. at a startup. Someone who leaves a mediocre corporate job after 6 months because he isn't learning anything and because it's obvious that no one with any power cares about him is, in my opinion, savvy and ambitious. This sort of person could easily be a great startup employee-- knows what he wants (and is therefore less likely to job-hop out of ignorance and confusion) and seasoned enough to cut through bullshit and avoid the wasting of time.
The cruel truth is that this business is so competitive, that if you make too many mistakes you're going to lose to those 1 or 2 among your hundreds of competitors that were lucky and competent enough never to have these kinds of failures.
In any case, I agree about the failure to distinguish fundamental (and very different) motivations here. Certainly you don't want someone crumbling under stress, but these kinds of people are easy to identify. Did that person had a very long vacation after leaving (for whatever reason) a startup? Does he seem to shy away from risk, stress, and high pressure positions?
If so, and you're hiring for such a position, it probably shows obliviousness and lack of self recognition and maturity for him to even apply.