Unrealistic Types of Damage

This post is basically to shed a little light on a commonly overlooked aspect of champion design. I'm assuming most of these abilities are like this for game balance purposes. But why does Galio's E deal magic damage? If a 200 ton colossus flies at me, I'd expect the damage to be physical (same thing with Gragas/Malphite). I know Riot has been taking steps to improve champion readability, but for newer players who don't have everything about every champ memorized, it might be a little confusing as to why a giant rock statue can still deal massive amounts of damage to them behind their Randuin's Omen, Thornmail, Dead Man's Plate, and Ninja Tabi. I mainly define physical vs magic damage as physical using some sort of solid object to impact the victim, while magic damage generally involves some sort of energy.

A few other examples that I thought of: W - Ki Burst (I feel this should deal magic damage) E - Make It Rain (They're BULLETS! They should deal PHYSICAL damage! HER ULT DEALS PHYSICAL DAMAGE!!!) R - Chum the Waters (SHARKS BITE YOU. BITES SHOULD HURT YOU PHYSICALLY) E - Electro Harpoon (I feel like the magic damage is explainable, but there should be a physical damage component of this) E - Audacious Charge (He's charging you. With a spear. Spears poke you physically, don't they?) E - Pillar of Ice (It deals 1 point of true damage. I'd assume this would hurt quite a bit if a HUGE pillar of ice sprang up from beneath my feet)

EDIT: I know these are almost 100% for balance reasons. My asking "why" is more of a rhetorical question, remarking at how silly it looks for a Lux laser and Gragas body slam to deal the same type of damage.