unreasonable gauge of wire being used (that can barely fit in the
screws without popping out),
The wire size looks normal, probably 14 gauge, maybe 12. That's what is used for lights.
the switch for the fan has two wires connected to the bottom. I
realized that it's a single wire, stripped in the middle as a loop.
But why the two connections? Does that actually accomplish anything to
tie to (presumably) ground? If you know it's ground, why not just tie
Stripping a wire like this saves time and is the best method to use when one wire is serving two destinations. The black wires are hot wires, not grounds. Most switches don't even have a ground terminal.
And the other wire goes into a hole at the top instead of the screw.
What... is this about? The nice new white switches to match the new
ceramic faceplate do not have the hole at the top; just the screws.
The hole in the top of the switch is an alternative to the screw at the top. You can connect to either one. The new switch is just made differently, i.e., without the hole.
You have to cut the wire to get it out, as far as I can tell.
You can remove the wire from the back of the switch by looking for the tiny slot near the wire's hole, inserting a flat-head screwdriver into it, and pressing down.