The reason why a lot of Linux libraries call exit() when OOM is imminent is not because that is best-practice. Rather, the reason is convenience, because Linux's OOM-killer will terminate a process with the highest memory consumption and lowest importance, as determined by it. So the rationale is "why bother"? The problem with this reasoning is that it promotes laziness.
The OOM-killer is a last-resort defence against a system failure caused by lack of memory. Designing a shared library that relies on the OOM-killer to handle OOM situations is like removing airbags from a car because it already has seatbelts. In other words, while it saves development time and effort, it is unsafe and not best-practice.
As we're all tech-savvy people, mostly with programming experience, some of us are professional programmers, what do we want to encourage in open source: reliable and safe software design and programming practices, or a "close enough is good enough" and "let's not do it because we can't be stuffed" approach to software?