Level 9 or lower legendaries as a general rule are hacked. But, so far the only available level 1 legendaries are Dialga, Palkia and Giritina. ( Giritina being in its origin form ). This is available through having an Arceus in your party, this arceus has to be a nintendo event Arecus, or from the Hall of Origin. Go to the Sinjoh Ruins with arceus walking with you,also being the only pokemon in your party. the lead archeologist will ask if you want to unlock a secret. bla bla bla you go through whatever, and Cynthia will show you to the three legendary beasts at level one, with their respective orbs.
People enjoy legendaries at level 1 because they can legitimately ev train them and what not to a personal level, just how they like it as a sense of their own. People ask for these pokemon because they must enjoy this, and therefore ask for them. They can be created to look simple and basic, just so that their level and what not is there.