That appears to me to be the wrong way to go about this, and it has specifically to do with how IoT security is a problem.
The most severe case of IoT security problems we have seen were things like mass botnets, where plenty of devices of the same type were hacked and then used for things like DoS attacks. Notable cases include the DoS attacks against Brian Krebs for some of his reporting.
The important thing to understand here is that the device owner is not the primary victim. That's a third party.
This is not about consumer choice, because consumers by and large do not care, because they are not the people being affected by this. An optional security label tries to adress it as a consumer choice problem, which it isn't.