Well, it was never my intention to do something that you would consider vandalism.
You're a good HN user and the only thing that's needed here is a bit more mindfulness. I like the 'arson' analogy for this sort of thing, except it's the wrong word since it implies intent. The right analogy is not arson, but negligence, i.e. playing with fire for fun or what have you, but then it burns down the building.
There's nothing intrinsically wrong with this thread. It's perfectly good watercooler conversation. That's part of the original intention for HN (let me dig up an old pg link...ah yes: https://news.ycombinator.com/item?id=8314). We all enjoy talking smack with coworkers or friends—same way one might argue about whether so-and-so is a good athlete or actor or whatever. On that level, what you did wasn't wrong at all, it's perfectly fine and good fun.
The issue is just that this particular watercooler gets broadcasted to millions of people, which suddenly makes for completely different dynamics. For example, the person you're talking about may well read the thread, which may sour them on HN and make them less likely to participate here, which would impoverish the site for all of us. That doesn't mean you shouldn't ever post criticism, but it should be alloyed with respect, and if the thread starts to turn into a cage match, you should do something to try to walk it back. (By "you" I don't mean you personally, but all of us.)
The biggest issue, though, are the feedback loops that happen when you're no longer talking to a couple people you already have good connections with, but an entire crowd of people who you have zero connections with. Your comments are guaranteed to get interpreted in ways that you not only didn't intend, but would find horrifying and would never dream of meaning. A lot of dark stuff flows in that way. Then people read it and feel licensed to start doing the same and worse—why not, if that's the kind of place this is? This is how internet forums decay, and the decay is exponential, so we have to be proactive about not letting that happen. That also is one of the founding intentions of HN: https://news.ycombinator.com/newswelcome.html.
Unfortunately, this does mean we need to have more restrained conversation than would be most enjoyable in a small group. People instinctively do this when talking to large groups, but HN is a large group that feels like a small group, so those instincts don't kick in. And of course it's also one of the best things about HN that it feels like a small group.
Past comments about this, if anyone wants a fuller picture:
https://news.ycombinator.com/item?id=21633967
https://news.ycombinator.com/item?id=15378909
https://news.ycombinator.com/item?id=9378899
https://news.ycombinator.com/item?id=7906377
https://news.ycombinator.com/item?id=7742471
https://hn.algolia.com/?dateRange=all&page=0&prefix=true&sor...