He's well known for almost torpedoing Lerna by committing an insane proprietary license where he called ICE and Palantir fascists who aren't allowed to use Lerna, and included into that any companies who ever do work for ICE or Palantir, which included Microsoft. Microsoft in response had to get to work dropping Lerna from all of its repositories, but instead managed to convince a different maintainer to boot Jamie off the Lerna team. While he was doing all of this he had the gall to call Babel and Lerna HIS personal projects. He wrote stuff like (paraphrasing) "I will not allow Palantir to use my projects." Multiple other maintainers of these projects had to point out to him that these were, literally, not his projects. At the time that he did this he wasn't even the maintainer or core contributor to Lerna. Long story short I will never support anything this guy does. It is incredibly irresponsible to put him anywhere near the levers of power of any significant project or to give him power over employees in a company.