Finally, somebody who's seen the same problem. I know the cause, but can't fix it.
The problem is that the ADT Pulse skill is a skill and not a Smart Home Skill. The differentiation is critical.
Both Vivint (ADT's bloodsword enemy in the home security industry) and Samsung SmartThings have allegedly qualified as Smart Home Skills.
The proof is when you look at the examples to call Alexa.
Simple Skills, you have to invoke the provider (in this case ADT). Thus, "Alexa, ask ADT to turn off the bedroom light"
You'll note that Vivint's skill and SmartThings, you can say, "Alexa, turn off the bedroom light"
This is because as properly registered and Smart Home spec compliant, all the z-wave devices the hubs have are then exposed directly to Alexa as smart home devices. Your proof is when you're in the Alexa app and click on the Smart Home and tell it to Discover and it doesn't find any of those switches.
ADT didn't/can't do that.
That's why you can't issue direct voice commands to your lights or switches and why Routines can't target them either.
Personally, I've tried to reach ADT about this. No luck. I'll probably have to buy a SmartThings hub and switch over to that and lose the automation from security events to the rest of my z-wave equipment.