I don't think JIRA is fully capable of being truly awful without people adding most of the awfulness to it. A awfulness-vessel rather than awfully-complete, but it is certainly part of the torment nexus humanity is building for ourselves.
I like to think of it as a Torment Nexus SDK. Start with a punishing UI (the web UI work and become unresponsive frequently, always wait at least 1.5 s before responding to interactions, etc.), add infinitely customizable bureucratic rules on top, and then make people's jobs dependent on making the numbers go up in the correct manner.
The worst part is that every company with a tasks product works right towards Jira. Compare what GitHub issues were in 2014 to what they are today: https://github.com/features/issues
I'm 90% those features were among the top issues on github/github repo back when it used to be there. The joke was always about how barebones github issues were was a common thing troughout the 2010s. Once they added that whole "Projects" thing, the joke became how complicated it is.
It seems like bad engineering culture though. If it was well engineered, then there would be simple concepts as a basis, upon which the product builds higher level, more complex things, that those targeted users think they need. Then there would be one API that is for the simple concepts, that lets people simply have tasks and get things done, potentially building a simpler UI on top of that API. The product itself could have a simple mode or higher level concepts mode.
If you read other people's comments here though, this is not what Jira APIs look like. Instead you have cruft built upon cruft, ever increasing in complexity, and seemingly no engineer was allowed to look back and fix things, find good concepts to represent things on a lower level. Lets build more features, accumulating more cruft on top, instead of fixing a broken design.