Bad news travels fast and a lot of the people on the board are repeat visitors so realize that they often know of the people involved and post their condolences which keeps the thread alive unlike positive posts that tend to sink into the oblivion. Jamaica has a population slightly larger than Toronto and the majority of that population is (obviously) in the big cities and Negril is not one of them.
Tourists are pretty much a protected species in Negril as it behooves the local businesses to keep it that way to avoid the negative affects of bad press and travel advisories. Most of the violent crime is Jamaican on Jamaican and, occasionally, a person who stays long-term around Jamaicans and less frequently a tourist in the wrong place at the wrong time. If you use the same common sense that you would at home, you should be quite safe and enjoy a nice vacation.
Respect.