Drywall and wood are wildly different than brick walls in stopping power, and I would absolutely agree that most bullets (even the lead-nosed [or soft] bullets) will go through several layers of gypsum and at least one layer of wood and retain lethality.

One correction: Green tips are different than you describe. They can penetrate low level body armor because of the steel core. They are not soft core. They penetrate low level body armor because the softer lead and copper jacket deform / slough off, and then the steel core continues to move through.

The M855 round was designed to penetrate through vehicles (doors and windows) and still be lethal to unarmored occupants. They just happen to be relatively effective at piercing low level armor as well.

Edit: To go back to my original thought: I still do not believe that these rifles should be leveraged by the police.