Most rooms don’t need acoustical treatment.

Inner Window sil shelves are cool? Ceiling tiles needed?

Re the OP,

"It’s snake oil, voodoo science."

Absurd falsehood. Every toom is different, and furniture and objects induce their own changes to the acoustical properties of the sound waves in the listening room, but acoustics are not voodoo science. If you could see soundwaves you would know this. Wind tunnel testing or a wave tank are demonstrations of wave theory and how the waves interact with objects they flow over—you can see it. Bass loading is a very common problem in untreated rooms, especially small ones. I am working with GIK Acoustics to tune my new-ish room now and tame the bass, reflections, etc. https://www.gikacoustics.com/

The AVroomservice guy is smart, and acoustical engineer by training iirc, and has good videos and info on his site. https://avroomservice.com/videos/

Jim Smith in his excellent book "Get Better Sound" talks about the room, and how spending lots of money on your hi-fi without treating the room (and setting up the speakers properly too), at least on a basic level, means you’ll never hear the full potential of your system. A modest system in a well set up room will often sound better than a more expensive system in a room that is untreated, especially if the room has inherent problems ( dimensions, ceiling height/shape, large/many windows, too live or too dead a floor etc). A room can be over-treated too, rendering it dead like an anechoic chamber. It's always a balance between none and too much. 

Why?  Because acoustical treatments presented are in virtually empty rooms. Unrealistic.

Not sure if you are making a statement or advising others. But you have also provided the reason why they are not needed, as it depends on a case-2-case basis. Yeah, your room is furnished and does not need treatment. My room is purpose built and was empty to begin with. A simple change in moving couple of treatments made profound positive changes in my case.
BTW, most forums also don't need duplicate threads. You have another thread on the same topic. Might want to remove it.

@patrickdowns,I have to agree with you.OP is clueless. But I think he is new on the forums and might be trying to "get attention".

Roger that. A quick search of the topic here would help him/her. I just searched "Jim Smith" and got lots of hits:

https://forum.audiogon.com/search/index?utf8=%E2%9C%93&query=jim+smith

jumia - Member since Jan 04, 2021