I completely agree, but as someone who's owned publishing for changelogs on large-ish, often super technical OSS projects, it can be very difficult to explain some of the concepts needed to grok a bugfix or low-level design change even in the span of a couple paragraphs. And more importantly, that context needs to be written by the engineer involved in the change, which means more context == less code work.
That being said, I think some projects do it extremely well. My gold standard for a while has actually been the OSS Dolphin emulator for Gamecube/Wii. They write incredible progress reports[1] every 1-2 months that give phenomenal context on how they found the bug, why it matters, how it works, and what they did to fix it.
Another great example is VS Code[2]. Their context tends to be around changes that are more UX-oriented, but it's still a great way to understand what new value you're getting on every new release.
[1]: https://dolphin-emu.org/blog/2022/02/08/dolphin-progress-rep...