>they’re infringing on copyrighted material
Sure.
>not following what they agreed.
They may have never agreed.
>that’s what bothers me
You can feel that way, but it's up to the copyright owner to decide if they want to go after such an infringement or if they are okay with it.
What’s you’re saying is asinine and simply against the GPL terms. Using the GPL licensed software code without following its restrictions is theft.
Vizio then should stop using GPL licensed software or reach to a license agreement with them BEFORE selling any product that contains GPL license because that’s the license of the code they’re using.