There is such a thing as threat modeling. The fact that your model only stops some threats, and not all threats, doesn't mean that it's theater.
Well, to be honest, theater is a pretentious word in this context. A better word will be shitshow.
(i never heard of a firewall that claims it filters _some_ packets, or an antivirus that claims that it protects against _some_ viruses)
What? That's all of them. Every single one. If they say otherwise, then you're being lied to.
There is such a thing as threat modeling. The fact that your model only stops some threats, and not all threats, doesn't mean that it's theater.