Some investors have more of a long-term perspective than others. Always the scary part of investing in early-stage startups has been the need to fund a lot of losers to cast a wide enough net to find the occasional winner. The main YC team will keep refining its procedures for searching out winners who haven't won yet, while screening out losers who won't win even with a YC investment, but that will always be an inexact art.
It comes across a bit harsh worded that way, but if you look at it purely from the point of view of a VC looking for a decent ROI, most of will be "losers" - most startups fails, and while many founders will try again and again and many will eventually make it, a large portion will never succeed at getting growth enough for an investor like YC to make a decent return.
If it was meant as a personality judgement, then I agree with your assessment. But if you view it as purely a statement about their odds of success at present time, it's just business.
But most startups fail because the product sucks. its not the people that "fail" in the market. The end-market could care less about "the people", in that sense. Its worth sanity checking even good heuristics, occasionally.