Personally, I see nothing wrong with hacking TMs or Moves, or even making certain pokemon to appear. I don't use the online features or trade at all so it doesn't affect that side of it. Recently I even hacked a Rapidsh to learn all TMs just so I could teach it Rock Climb. I don't see a problem when it's for your own entertainment really. Plus, I'm not going to train Pokemon for hours to evolve them so I might use a fast EXP gain code from time to time. It depends on what I want it for, but usually for hacking in specific items or something. Like wanting a Steelix but not being able to get a metal coat. I see no shame in hacking one in.
Maybe I take it a bit too far? :/