[electromagnetic]

Not necessarily, it depends what causes the defender to draw. It may take you ~200ms to react, however it also takes the drawer time to act on their decision, and may take longer as there's an incentive to aim as there's no point in shooting first and missing.

Button pressing /= drawing and aiming.

The defender has less incentive to aim, and besides your brain already has the calculations made. In hunting the snapshot is a frequent killer due simply to reaction with no conscious aiming. IIRC the NRA has ~40,000 bullseye shooters who have to have rapidfire accuracy on multiple targets to attain the grade. This requires the ability to make snapshots.

I'm not going to believe any result on gunslinging until someone picks up a properly weighted pistol that has to be aimed and fired (whether it be a blank or using an LED sighter). Otherwise it's not scientific, you're fucking with the variables and the very nature of the experiment.