I lean towards agreeing with you, and I'd probably behave like you if I played the game. But one way in which you (in the aggregate, of "cheaters") do hurt others' experience is by artificially diluting the rarity of pokemon. That's a part of the experience for other players, which if you use tools to help yourself, indirectly is harmed. Not you personally, but the fact that such tools exist and people are using them.