It's not just a "virtue signal"; those packages will have to go through some special (and pretty aggressive) transpiling in order to work. This wasn't just flipping a switch from the Deno team
We are consuming sources as they are provided in npm using "compat layer" that is part of Deno's standard library. We had to provide special module resolution, but besides polyfill for built-in Node APIs, it works very similar to how Node consumes these packages.