I don't understand either but it's a habit I've had a hard time breaking out of "full stack" developers.
Bashing DOM nodes together to do a task is merely one manifestation of this. Multi-thousand line functions, code that makes thousands of queries to a DB and manually performs some enormous task that could have been more easily done in three slightly more complicated ones, code that just flings open a socket every time it needs to do something on the network and just starts stuffing bytes at a remote service... it's all manifestations of this.
I don't have a good word for this. I wish I did. Probably something buried on C2 somewhere if I poke around hard enough.
These are the things that get cleared up by code reviews, break sprints, bug hunts, periodic refactoring… in many cases, YANGTNI applies. That's not an excuse for long-term sloppy code, but it's an excuse for developing good practice when making changes to an existing codebase.
I suppose that's what I was getting at originally. There's absolutely nothing that removing or adding jQuery will do to impact the larger problem of treating client-side development as software engineering instead of incoherent scripting. None of the advice on the originally posted site would change those organizational/logical problems.