Hey now, at least they bothered to respond to you with a few sentences and some advice. Most of the time they don't even write you back, let alone personalize the rejection.
And seriously, don't beat yourself up too much. They didn't say that your work wasn't good, they gave you the "know your audience" spiel. That means that they think somebody else might pick it up, but that they aren't certain your idea works for their particular specialty. If they thought it was out and out bad, they wouldn't have bothered to give you encouragement. Trust me on this - editors don't have time to write personalized messages to the thousands of submissions they get every year. If they take the time to write you some advice, they see something in you - its just not the something they are looking for.
Have you tried using the Writer's Market books? They publish a new one every year, and it lists a lot of magazine editors - as well as what the editors are looking for. Most library carry a recent enough edition (or you can just "browse" at a bookstore and copy down a few addresses for promising editors). Or you could >GASP< pay the thirty dollars for it...
Also called "The Freelancer's Bible": http://en.wikipedia.org/wiki/Writer%27s_Market
edited 2nd Nov '11 8:23:10 PM by MyGodItsFullofStars