So much irony here. So, the community can be careless and just import whatever, but the maintainer can't pass maintainership on to someone else without it being dubbed careless? Shouldn't this whole situation be the fault of the community because they let in a bad actor? Society is great when everyone is benefiting, but something goes wrong and out comes the pitchforks.
Don't get me wrong, I believe the author's heart is in the right place. I find his willingness to be inclusive and get other people involved refreshing actually, but the problem is that he should know better. He's seemingly used npm enough to know that there is no mechanism within npm to notify downstream modules that he is transferring the package to someone else (and that there is now a new security risk that they must re-evaluate). The course of action taken was simply not thought through. I'll leave it to others to explain what the appropriate course of action should have been, but keep in mind that society is built on trust, otherwise you have nothing to build on. You're too busy doing every job instead of one that builds upon others.