Malaysian Airlines is in fact voted as one of the safest airlines, but could still encounter this unfortunate event...so it's nothing to do with Malaysian airlines. For some other major airlines, e.g. Air France, BA, China Airlines are said to be not as safe before Malay has this incident. If it's me, I would choose to go.
The social order in KL isn't so bad, as long as you don't go to quiet street, return to hotel not so late. If late in the street, take taxi. Don't over worry. Streets in some European countries could be even worse.