pg seems to be of the latter stripe, so it's no surprise that Hacker News reflects this bias, and will continue to do so in the future.
There are already a thousand other general news sites, or even tech news sites. I come to HN specifically because it satisfies one niche very well. It is incorrect to suggest that attempts to keep a site on-topic and focused implies that the people doing said guidance don't have outside interests.
You are tempted to try to broaden the definition of that niche site but pushing it's boundaries. It is up to the site to push back on you and resist that.
I think there is a lot of confusion around what qualifies as "Hacker News" both in tone and scope anyway. The niche is ill-defined. I could probably even defend a position that focusing on startups isn't really hacker news either even though it's clearly an interest of pg's.
If we start from the assumption that if somebody writes about something that he is interested in it, then would you please categorize the following list into 'one or two little areas' ?