Come on, use common sense.

I never said bash their skull either.

The instructors mean, in general; if you're trying to get someone to put their hands behind they're back and they're not complying, but don't pose a severe or direct threat to you yet; it would be more suitable to use some defensive tactics with your hands, baton, asp, or flashlight to get them to submit; rather than using Pepper Spray for something of that nature.

When it comes down to a fight, a serious one where your life is in direct danger, there are tactics and there is training, but every single one of my instructors ends his instruction with "Do whatever it takes to win the fight and walk away alive. My instruction is just here as a guideline."

So in those cases, use what you've got, and use it anyway you deem necessary. Afterall, that is a life/death situation (if it occurs)