What a creative way to solicit new business. These quarterly touts for work on HN in the guise of AMA leave me somewhat annoyed.
No one is asking you to read them. Feel free to ignore it. I don’t see anything wrong with YC’c immigration attorney doing an AMA on HN which is hosted by YC.
Any decent immigration attorney who works with tech companies has a virtually unlimited stream of work available. I very much doubt this is the reason for the posts.