The sidestand switch is just 2 wires. The circuit must be closed (the wires connected) for the bike to run while in gear. If you simply disconnect the switch from the harness or cut the wires the circuit is open and the bike thinks the sidestand is down.
The 12 O'Clock labs solution is a simple connector that replaces the sidestand switch and wires with a connector that has the wires connected to each other. It's a clean solution if you want to restore the sidestand switch again later by just plugging it back in.
You can accomplish the same thing for free by just cutting the two wires anywhere on the harness and soldering them together. The only downside to this approach is that you'll need to unsolder and reconnect them to the original wiring if you ever want to use your sidestand switch again in the future.
I did the cut and solder method on my bike and it works fine.