But they don't; even moderately competitive players can beat the best bots.
That's because the programmers are bad at AI for that kind of game. It just means human beings don't understand how to make a good AI for a game like starcraft. AKA the human being being the idiot that doesn't understand how to make one.
This isn't true, in general a bigger army will beat a smaller army every time.
After you can make equal size armies, the next problem is army positioning and when to take engagements.
Finally, after you can do all that, then you can get an extra bonus to your power by microing really well. But not every micro is about speed - most of the time it's about knowing what to do.
And even at the most extreme, it's less about clicking quickly and more about clicking precisely.
Yes, anything where the interface to the game becomes critical is difficult to fairly compare with humans. Board games can use a human as an actuator, micro-heavy games hopefully won't for a long time...
Didn't they just try to sell that department?
If you want "fairness" you can limit the instructions to what keyboard and mouse can actually interpret as in the limited latency between instruction that both the game, the OS, and the hardware can support.
https://en.m.wikipedia.org/wiki/Fitts%27s_law
It may also be interesting to model the state of the keyboard hand. Instead of allowing the computer to access keyboard shortcuts directly it could be forced to operate a virtual hand that is in turn operating a virtual keyboard. Constraints could be added to the speed of various finger movements. This provides balance but also captures authentic strategic tradeoffs. Like the resting position of the hand. I imagine if you had a nice visualization it could even reveal subtle optimizations that were practical for humans.
USB has quite a bit of limitation for HID's and allot of the gaming mice and keyboards use various hacks to overcome them.
Games and OS also have limits I can easily issue more commands using my keyboard than SC2 can handle so not all key presses will actually register.
Not to mention is that the game actually has to run on regular hardware, start spamming your keyboard in a game and you see the CPU spikes, the game loop also puts quite a bit of limits on how many interrupts per second it can catch, and how long does it take for it to actually switch context (e.g. SC2 build menus).
That said after AlphaSC2 destroys another Korean national passtime I would definitely love to see human like input being used by AlphaSC2.
Not because I think humans deserve a fair fight, but because i think the most interesting part will be to see how AlphaSC2 has to modify it's play style to compensate for the limitations of having to use "meatbag" control methods.
The AIs unit control speed may have to be limited to get interesting results where it has to use strategy.