Is it really unclear what the issue here is? The issue is that the OP was too promotional. Indeed your account history on HN has been, basically, entirely promotional. That's not really what the site is for. This is in the guidelines: https://news.ycombinator.com/newsguidelines.html.

On HN, the idea is for people to submit stories that they ran across and personally found intellectually interesting, not because they have something to promote. It's fine to post your own work occasionally, as long as it's interspersed with interesting posts from other sources. But if you only submit promotionally, it feels like you're not participating as a community member.

To be fair, the stuff you've submitted has been good, certainly not spam. But the newsletter thing was a step too far.