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.
Seems unlikely since lawyers have a notoriously high un/underemployment rate. Unless we are using circular reason to define "decent" as anyone with unlimited demand.
“All lawyers” is a meaninglessly broad group to compare to “experienced immigration lawyers with strong connections in an industry that requires a lot of immigration lawyers”.
"Any decent immigration attorney who works with tech companies" is very different from an "experienced immigration lawyers with strong connections".
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.