Earlier quoted context omitted.
How does a 30-day notice work unless you have a way of reaching out to people using your modules? It just seemed so unrealistic that even 1% of people would actually see such a notice before things start to fall apart.
You bake deprecation notices into npm, to be displayed during install. He has more than 3m installs a month, if he really wanted to, he could have easily display a giant "npm sucks" banner during every single install. Same message, but it wouldn't immediately hurt people who trusted his modules.
Perhaps he wanted (because of his rage on npm) to hurt people that trust(ed) npm?