Is amperage constant or relative to the device?
You should immediately disconnect this and be thankful nobody got electrocuted and your liability insurance company didn't find out about your wiring.

The current that light draws is small enough that it should be no issue for those wires.  22 mA sounds too small, so either this light is much smaller than it seems from the picture, or you are measuring the current incorrectly.  However, it would have to be a 115 W light just to draw 1 A, so that's not the problem with your wiring.

The 20 A rating means that's the maximum the circuit can supply without the breaker popping or the fuse blowing.  Each individual appliance decides how much current it will actually draw.

The problem with your setup is safety.  You have dangerous voltages exposed.  It is too easy for you to accidentally touch one of the live wires while some other part of your body is connected to ground.  That would hurt and shock at the least, and could kill you under the right circumstances.

If you want to rig up this switch yourself, turn off the breaker, solder the wires properly, then wrap everything carefully with electrical tape so that no conductors are exposed.  If done right, that would still only be safe in a practical sense but not a legal one.  If someone gets zapped, even due to something else, or your house burns down, your kludge could give the insurance company the excuse it needs to not pay.  Even worse, you could be legally liable for someone's injury, even if your kludge was not at fault.  I'm no lawyer, but assume you'll have a uphill battle to prove your kludge was not at fault, rather than the other side having to prove it was.  This can be what happens when you make illegal modifications to power wiring.