304 votes, 75 comments 3 hours after posting and this is already being thrown all the way back to 134 rank on the front page with some 2-3 day old posts. This is very clearly hacker news: a case of opsec slipup in easily the worst fashion coming straight from the SecDef (or one representing the SecDef). A shame it is probably getting flamed and downvoted over partisan reasons, although I know there are many conservatives here who probably don't enjoy these constant leopards eating face moments they've unleashed and am not surprised they'd be acting out and flagging embarrassing posts.
People often flag politics-related posts because the comments are invariably of low quality. The interesting discussion is generally about technical issues, but that is usually overwhelmed by political opinions. This happens on both sides of the spectrum.
There are lots of other places to discuss politics.
this site has some governors in place to prevent a flood of low quality engagement. If things rise too fast, they get pushed down a little and cool off and rise back up. No great conspiracy as I found this thread at the top of HN a day later.
On-Topic: Anything that good hackers would find interesting. That includes more than hacking and startups. If you had to reduce it to a sentence, the answer might be: anything that gratifies one's intellectual curiosity.
Off-Topic: Most stories about politics, or crime, or sports, or celebrities, unless they're evidence of some interesting new phenomenon. Videos of pratfalls or disasters, or cute animal pictures. If they'd cover it on TV news, it's probably off-topic.
Not sure that 'fat fingering' on a mobile device rises to the level of tech-related opsec. The choice to use a non-government approved device certainly is news, but not necessarily Hacker News. Plenty of better places to debate it.