Ebola Reston evolved naturally, and emerged in humans due to an infected lab monkey imported from the Philippines to a contract research organization in Reston. Anyone who guessed that it came from Fort Detrick would have been wrong about which lab it came from, but right that it came from a lab.

Put differently, if scientists there hadn't been experimenting with monkeys, Ebola Reston wouldn't have entered humans there. We don't absolve exotic wildlife traffickers or farmers of the consequences of their actions in releasing novel, naturally-evolved viruses; so I'm not sure why we'd absolve scientific researchers.