At least in theory, while the journalist isn't a subject matter expert, they have spent time reporting on the same domain. They know the people who are experts, and work under an editor who has worked in that field for decades. They should be able to validate any facts and be able to put them into context.

As newspapers have gotten hammered there are fewer and fewer people who actually do that, and more and more bloggers with loud opinions and few facts. Many good sources have gone defunct or given up trying. But there do remain a few sources of decent journalism, where the reporters and editor really are better informed than most laymen.