Converting parallel printer switch into USB KVM switch
USB is a system that uses what we call "differential pairs", because it is a very high speed system.

A differential pair is designed to be coupled together at a very specific coupling. Like in UTP cables, the signal wires are put into the cable at a very specific recipe, so that the impedance seen by signals of those data wires fits an exact specification.

Once that impedance changes more than 10% over more than a very small section problems occur with the signals. They start echoing and bouncing up and down. It'll be like trying to communicate a very delicate series of instructions in the most echo-y room you can imagine.

Adding a few loops of wires or such very likely creates a deviation of more than 50% at a local point. That point will be the hard brick wall in my analogy that is the surface those signals echo against/from.

If you don't know specific recipes for keeping USB signals perfectly coupled, or close enough to it, you'll create such perfect brick walls that nothing can use your system to properly communicate, because all they will hear is echoes.