The safety record of Lion Air is but one piece of the puzzle. Regardless of their history, they can still be involved in an accident that is not the fault of the crew. If you are biased at the start of an investigation you are likely to miss vital clues. On a purely statistical side note, many well known carriers have a higher fatality record than Lion Air.
Significant investigative effort should also be placed on examining the procedures, training, and corporate culture at the accident airline.