In the immediate aftermath of Flash Airlines 604 it was thought to be terrorist related but this was very quickly dismissed, even though retrieval was more difficult. I note the accident happened on 03/01/2004 and the final report came out on 25/03/2006, so all things considered, pretty quick.
If security in Sharam el-Sheikh airport wasn't up to scratch wouldn't you imagine some of the 900,000 British who visit each year and can compare it to UK airport security would have drawn attention to any perceived shortcomings?