The airline does want to be associated with the accident.
If joe nobody, who doesn't pay attention to the news, happens to be passing on that bridge near where the garuda 737 went down, he will not exactly have a positive association to make with the airline.
In short, the airlines pressure local governemental agencies to allow the logos to painted off as soon as possible, and it is sometimes even joked that these painters arrive on the scene of a crash before the accident investigators do.