As soon as you say, “I was looking for a library,” you’ve already indicated that you feel entitled to find a library somewhere rather than build it yourself

That interpretation is completely on you. Whenever one is writing code, it’s good practice to check if it hasn’t been written before. No-one needs to re-invent the wheel for the umpteenth time.

Do you not understand how that comes across as entitled?

No. This approach is literally taught at Uni. Don’t repeat work. That’s not only in programming. A chemist’s saying is “6 months in the lab can save you 2 hours in the library.” Blindly doing everything from scratch is just incredibly poor use of resources.

You’ll reject a GPL licensed library because it is copylefted and you know your management would never go for GPLing the entire work.

Yes. I don’t see how that’s a contentious point. I think I made my position clear in my last comment.

why do you expect there to just be some library you can use internally

That assumption is based on experience. The whole JavaScript ecosystem thrives on the idea of building stuff based on others’ work. It’s you, btw, that chose to interpret ‘looking for’ as ‘expecting to exist’. I never said that, nor did I mean it.