I disagree that it's a false accusation. YCombinator benefits financially from putting their job postings on the front page, I think we can all agree on that. You seem to disagree that it's "manipulation" to make their job posting look nearly identical to a normal, organic user submission. I think it is a subtle dark pattern and explained my reasoning.
You can't vote on it, you can't comment, and the title fits the pattern I mentioned earlier - it's absurd to describe this as "nearly identical" to the normal submission. Having occasional, untargetted, marked, on topic advertising on a free site is about as far from "dark pattern" as it is possible to be.
A dark pattern has nothing to do with whether they're justified in doing it (for instance, because this is a free site). The submissions could be marked with "YC Sponsored Post" they're still totally justified in doing it, but it would be less of a dark pattern than it is now.
