Ask HN: Why are comments disabled for the “X is Hiring” posts?

Just an honest question I had... I would have thought that these hiring posts from YC companies would be a great vehicle to advertise their company product, culture, etc., especially since the posts themselves are artificially boosted.

More than once I've thought -- "that sounds like a cool company, maybe their founders would do an informal Q&A", only to discover that there were no comments.

Is it because they got flooded with negative comments about the company in question?