I didn't think I would have to spell this out, but when I wrote "as much as possible", I was acknowledging that some libraries are either too complex or too security-sensitive to be reasonably homebrewed by the unqualified. (Perhaps "as much as reasonably possible" would have been better phrasing.) Where the line lies will depend on the person/team, of course, but the vast majority of libraries do not fall into that category. I was generalizing.

And yes, some third-party libs might get so much public scrutiny as to be considered safer than what someone would create in-house, depending on their skills. But safety in numbers sometimes turns out to be a false assumption, and at the end of the day, choosing this approach still pushes external risks (attack surface) onto users. Good luck. It hardly matters to the general point, though, because most libs do not have this level of scrutiny.

Let's also remember that pinning dependencies is not a silver bullet. If I didn't trust someone to follow "best practices", I don't think I would trust their certification of a third-party library hash any more than I would trust their own code.

With all that said, let me re-state my approach for clarity:

I minimize dependencies first. Standard libraries are great for this.
When something more cannot reasonably be avoided, I choose very carefully, prioritizing the safety of my users over my own convenience.
Sometimes that means changing my original design, or spending my time learning or building things that I hadn't planned to. I find the results to be worth it.