I think there's a lot of reasons. Part of it is that, as the power of the tech industry has grown, journalists have become more active in exposing how it abuses that power to make the country, and the world, a worse and more degrading place to live in, and people on HN don't like being reminded of how they contribute to that.
There's also a ton of people who are just reflexively hostile to the idea that society is systematically unjust and exceptionally hostile to the idea that they benefit from the ways in which it is unjust, and as mainstream journalism has been largely sympathetic to these ideas, they are in turn reflexively hostile to mainstream journalism.
There's also a ton of people who are just reflexively hostile to the idea that society is systematically unjust and exceptionally hostile to the idea that they benefit from the ways in which it is unjust, and as mainstream journalism has been largely sympathetic to these ideas, they are in turn reflexively hostile to mainstream journalism.