Indeed. Churches, as churches, should focus on matters spiritual and eternal; individual believers, of course, are free to apply their faith and its principles as they encounter this temporal, passing-away world, and engage in whatever activism they please, as they feel Spirit-led.
Your fundamental error remains thinking that Biblical preaching, sacraments, prayer, and the like have little value.
There will come a day when your physical body and the material things of this world that you value will pass away, including the people who are dear to you. What then?
The only beef you should really have with the PCUSA is that they are concerned about societal transformation and political activism from the left and not from the right.
This is the problem with the culture war — it’s mostly a fight over who is going to control the spoils in this world. No one on either side is that concerned about the life to come.
We’ll all spend a lot more time dead than alive, though. What we see is all temporary in the form we see it.