I would expect "untrusted code" to mean "code in a sandbox" or "code I'm not gonna run at all anytime soon", so running code from thousands of dependencies in node is effectively trusting all of that code, unless it is your direct expectation that it is malicious (and even then, aren't you trusting it to be malicious ?).

The trust we give to random dependencies like that is quite arguably unwarranted to a large degree, but it doesn't mean the code isn't trusted.