I've seen some well-written library code that is kept up-to-date, and I've seen some crufty libs that, frankly, would barely pass muster on an internal code review. A good litmus test is to check the linting configuration for a given library repository, as well as the frequency by which a given library is updated. And none of these are anything that an experienced developer wouldn't do otherwise, regardless of the code.
To the original poster-sorry your life has been beset by having to clean up the messes of others, though you will find this to happen again and again. Grow up a little–some engineers might see this as an opportunity to make their corner of the world a better, more functional place, whereas a younger, more entitled engineer might expect everything to be perfect on day one (HINT: it isn't).