This is (quite obviously?) wrong. One doesn't imply the other at all in any way shape or form. If this were true, there wouldn't be a single device on the planet, including phones, servers, etc. with remote update functionality that would be secure, ever.
Also
>If there's a backdoor for law enforcement, there's a backdoor.
duh? But I think what you are trying to imply is that "there is a backdoor that criminals could use" - which is also wrong. As long as the implementation is correct and the key isn't leaked, this is completely secure. Of course it'd be insane to have one key being able to unlock essentially all communication within a huge system, because chances are it might be leaked eventually, but that has absolutely zero impact on the fundamental possibility of making this system secure.
You're so, so close to waking up from the matrix. Very excited to have you join us in the real world soon! Follow the white rabbit.
"And where can I read up on google's infallible firmware signing strategy that you're implying has the ability to block exploits and bugs?"
I have no clue where on the scale of "state action" -> "bribed/coerced insider" -> "disgruntled ex google employee" -> "Elbonian strip kiddie" you need to be to "control that lamp", but I'm 100% certain that the reality is that the capability to revert this new lamp behaviour is not exclusively in the hands of authorised Google employees...
It's exactly the same as the current encryption bullshit. If there's a backdoor for law enforcement, there's a backdoor. If there's a remote way for Google to update the Nest software - there's an exploitable remote way to update the software.