I don't think he's doing that at all. He merely observed a negative pattern that many startups tend to fall into by default, and warned people about that pattern. The tone of the post is clearly "it's easy to make this mistake, don't make it", not "if you make this mistake you're an idiot." The latter interpretation is perhaps the least charitable you could have picked.
I do think there is a kernel of truth in your comment. YC tests a lot of assumptions and tries a lot of things. Many of the tests work out, some don't. This means that at some point they've necessarily given founders bad advice that people then went on to execute on. I think that's something worth acknowledging explicitly (e.g. "hey, we thought this was right but it turned out to be wrong; sorry"). But there is a huge gap between that, and what you referred to as "crapping on alumni".
I don't think he's doing that at all. He merely observed a negative pattern that many startups tend to fall into by default, and warned people about that pattern. The tone of the post is clearly "it's easy to make this mistake, don't make it", not "if you make this mistake you're an idiot." The latter interpretation is perhaps the least charitable you could have picked.
I do think there is a kernel of truth in your comment. YC tests a lot of assumptions and tries a lot of things. Many of the tests work out, some don't. This means that at some point they've necessarily given founders bad advice that people then went on to execute on. I think that's something worth acknowledging explicitly (e.g. "hey, we thought this was right but it turned out to be wrong; sorry"). But there is a huge gap between that, and what you referred to as "crapping on alumni".