Unwanted trades

Why do some trainers not add cool or uncommon Pokémon to their remote trading lists?

I’ve a few remote trades available with trainers but all they have tagged are multiple basic shinies like Charmander and weedle or something. Or regular ones that are most likely caught like Dragonite or Charizard or something.

My experience is that they request rare or legendary ones but they have pretty poor options back. I’ll do an uneven trade but cmon man 😭