I need someone to explain why...

When you say normal do you mean blind pick? If so that might be the reason right there. Other than that people in normals are more likely to play fast and loose and once you feed a morde the metal man becomes the metal monster. When it comes to a draft mode though you are more likely to get counterpicked which can really hurt a lot of champs.

People don't take normals seriously (because they're normals). Junglers tend to just farm and games devolve into 5v5 TDM in midlane. In ranked, you're going to get camped because you're a mordekaiser, which is one of his most exploitable weaknesses.

Normals.. Draft or Blinds?

Draft tends to be fairly orderly. But blind pick is a clownfest where anything goes, people suck, and half the players are trolls, joking around or playing bizarre offmeta stuff, and nobody can counterpick you.