remember when i traded a honedge for an yveltal over the GTS?
b/c i just now managed to GTS a monferno for a goddamned Kyurem
granted, the monkey was level 100 but that's still a common/legendary trade I can't loving believe happened
Bear in mind that legendarys aren't all that rare, since everyone gets them. Of course most people want to keep them on their main game because there is only 1 and they've played the game and worked towards getting it.
But then there are players who restart the game, having saved their original legendary elsewhere, or play on a second cartridge, so the legendary is worth less to them.
Then you get moments like yourself where someone does get an extra legendary through GTS, either legitimate trades, stupid trades, or wonder trades. So people do end up with spare legendary pokemon that they don't mind trading away.
Not to mention that you did just trade a level 100 (always attractive) monferno, which is a starter pokemon and therefore for most players is equally rare if they don't have a female to breed or a ditto, or the time and patience. Plus the fact that it is a gen 4 starter means no one has guaranteed access to it in X/Y, unlike the legendary pokemon which everyone can get.
Legendary pokemon are rare and all, but they're not irreplaceable, and your own offer is fairly rare anyway.
