I completely agree, with regard for the GP's point about Android TV's with onboard ffmpeg libraries and Addon Apps that call on said libraries (or pull in their own) ..
Cheap arse low resource TVs should either include some form of sandboxing OR the entire device should be treated as a "can fall over" sandbox .. well isolated from any household LAN of consequence, etc.
It seems unlikely that BoxStore Brand Android TVs will be well designed with an eye to security so <shrug> they're an exercise for home net admin masochists and/or an opportunity to market sensible easy to use IoT age routers that come preconfigured to handle bad-device(s).
Am I getting this right, you expect TVs which are running Google TV (Android TV is the old name) to be less secure than TVs which are running a different operating system? I think the opposite is the case, because Google TV is developed by Google, which has a lot of experience with software security, while other TV operating systems are developed by companies which clearly don't have that experience.
There are a lot of "Android like" TVs out there.
Those are running mainly on Google TV. Tizen or webOS are also common but are not based on Android.