Why do the Pokemon of the Trainers in Gyms know moves that aren't supposed to be learned until later levels?

Question

I'm so jealous; this one guy had a Gastly level 19 and it knew Sucker Punch, which Gastly doesn't learn until level 22. What's up with that!?

Comments

and on the first gym on hg ss a lv 14 pigioto when it doesnt evolve till something like 17 or 18 :)

---

and a level 6 venemoth appears in the wild in hg ss too..

Answer 1

Because that's the way the programmers made it. Often, they try to have one common move as the "TM" move that you can get to show you what it can do. They also have to accommodate the player with reasonably leveled pokemon so you aren't getting overpowered too early. You can program the pokemon to have whatever moves you want (they can even do illegal sets, but they choose not to.) So does it make sense that Gastly knows sucker punch at level 19? Not quite. Does it make sense that most of those trainers have really high leveled pokemon that past their evolution level, but are still in their basic form? Not so much either. You can only get so much logic from a children's game.

Comments

Guess the same can be asked of why some evolved wild Pokémon are at a lower level than they are supposed to be when they evolve. 'Cuz they were programmed to. (Not counting the Gyarados in G/S/C/HG/SS Lake of Rage)