Well, not exactly.....what they found was one neighbor (Suann Adams) who said the police were there first. Nowhere in the article do the police retract their original statements about neighbors being present in the house when they arrived. In fact, the district attorney's comments at the end of the article clearly suggest that he believes neighbors were present when police got there.
Your suggestion that the thought of this being a runaway case might have delayed the police in securing the scene may be correct. On the other hand, I think it is possible that the police found themselves in the presence of some very influential people when they arrived, and they were reluctant to start issuing orders.
(And before you ask, no I do not have a "guest list" of the people who were present......this is simply speculation based upon knowledge of the Smarts' social status and the general affluence of the neighborhood.)
As I said earlier the article was poorly written. It still leaves some ambiguity. The key point in the article is that the police are taking responsibility for the problems with the crime scene. In doing so, they are in essence retracting their original statement. My guess is that the original statement came from detectives who arrived much later than the first patrolmen. The detectives found the house full of people and were dismayed at the situation. This was caused by the patrolmen not telling the Smarts to keep people off of the property. The Smarts should have thought of this themselves, but basic crime school knowledge is not a prerequisite for parenthood. Once again, the key item in the article is that LE has taken responsibility for the problem.