Maybe there's an actual canon reason but my take is this.

The Borg, being a hive mind intelligence of sorts, know where all the cables are going and ran and it's in their memory banks what goes to what. So, in order to make it easy to change or fix things, they just leave the cables hanging around willy nilly as they don't need any guidance one which cables do what or go where. This also confuses ship boarders who might be trying to tap into a specific cable on the ship.

Idk ... It's stupid but so are the borg.

It's the I.T. way.

What do you mean? That is superior to what I can manage.

answer: this is actually what good cable management looks like

Cable management and purely performative aesthetics aren't beneficial so why waste time with it

I think I've seen it suggested on similar posts that it's an amalgamation of best practices from various different cultures they've assimilated so it works for them because they understand a method to the madness that we cannot

is the cube functional? bc that looks functional to me.

get functional.

Their species has low dexterity. They don't have the fine motor skills to route cables and their brain(s) haven't evolved to notice or care.

You may not like it, but this is what peak performance looks like

Real answer is probably AI slop. Several companies have the idea that if code is only going to be done by AI, then it doesn't matter if it's human readable. I imagine this is something like that but for cables.