Lower chest exercises

Why is almost everything here a dip?

Because the dip is the only movement that puts your arm exactly where this category wants it: torso leaning forward, arms traveling down and slightly back. The descriptions in the atlas come back to this on every version, always with the same line about the lean - without it the same movement turns into a triceps exercise.

The second thing is load. The dip is the only bodyweight chest movement you can add weight to directly, and it shows in the list: next to the plain version sit weighted variants, paused ones and weighted ones done slow. The rest of the equipment-free exercises have no such path.

Beyond dips you are left with the decline bench and a few machines. There are not many, because a decline bench is equipment that not every gym owns and that basically nobody has at home.

How much of this list is really lower chest?

Less than the name of the category suggests. The chest is one muscle whose fibers run at different angles into a shared attachment on the arm. Where you put your arm changes which of them work hardest, but it does not switch the rest off. Anyone who benches flat or does push-ups is already loading the lower fibers.

The practical conclusion is that lower chest is an emphasis, not a separate workout. You see it most clearly in dips, because there the forward lean changes the angle a great deal. With the push-ups on this list, raising your feet or dropping to your knees mostly changes how much of your bodyweight sits on your hands - that is a matter of difficulty, not of which part of the muscle works.

The short answer for anyone who wants one thing: dips with a forward lean. If dips are still out of reach or your shoulders complain, the decline bench does the same job in a version that is easier to control.