Yes.  But you can also do the same with your hand, and a regular stock on the gun, so why does it matter?

I can fire a semi-auto weapon (pistol or rifle) at 100% the same speed with a standard stock, as you can with a bump fire stock installed.  It only takes a couple of hours to master the technique, which just requires you hold your weapon differently than normal (so it is awkward at first).

Does that mean my finger will be illegal and I'll need to license it with the government or they will take it away?

And Feinstein's law is completely stupid.  Technically, cleaning and oiling your weapon will make it cycle faster (marginally), so will gun oil be illegal?  A smooth trigger can improve it, so will there be a minimum mandated trigger pull and stroke? What about piston vs gas driven AR's, since cycle rate can be different there?  Buffer weight? Spring strength?  Suppressed?  All these can increase cycle rate, so all could be regulated under Feinstein's bill!