DominicCobb said:
It’s one thing if he’s just sniffling over it, it’s another thing if he’s got a lightsaber and killing his father (amongst all the countless others). I can’t help but think about his implied massacre of Luke’s Jedi Academy - there’s a real school shooter vibe there. I don’t think that’s very funny at all.

How did he kill all of these Jedi trainees when he couldn’t even kill one who was untrained?

There is no consistent logic in the world created by Abrams and co. TFA has no consistent internal logic. The characters don’t have consistent motivation or characterizations.