You're right, it's not always the case, but in that format the second sentence is usually a justification of the first. Also, Black Mirror is not a comedy.
Every time I watch it I'm laughing my ass off. It's definitely not serious, or even satirical.
Most sci-fi has the problem of trying to model a situation with limited social scope. The fact that they never turn out true is because society has social safeguards to prevent it from happening that the writers don't model.
We call it a comedy when it _intends_ to make people laugh. Just because _you_ laugh about it, doesn't mean that it also intends this.
I know you could now say that they actually intend it. But I doubt that. (X)
Don't take it seriously.