It's obvious, what is going on here. He's got two groups he's trying to reach and "the front page of HN" isn't one of the groups. The first group is his mailing

It's obvious, what is going on here. He's got two groups he's trying to reach and "the front page of HN" isn't one of the groups. The first group is his mailing list. People who have expressed a general interest in what Patrick has to say. Patrick is investing hours (probably) into each mailing and knows there are people who have a specific interest in each one of these mailings. Through the Magic of the Interwebs it's possible that this second group of people with a specific interest could possibly find this mailing if only he would put it on the internet publicly. And for various reasons putting it on his blog probably isn't the most advantageous way of putting it out there publicly. I hope your day improves, because it looks like it isn't going so well by the tone of your comment!