It means the future elements in scifi (when it is about the future at all; some scifi doesn't even pretend to be futuristic) are an extrapolation of the current time and used to explore an idea about today.

An author's scifi "gimmick" (it can be a technology, a societal norm, an alien encounter, etc) is often the way in which the author develops and extrapolates a preoccupation about the real world, be it war, or invasion, or social alienation, or consumerism, etc.

The most obvious (but least interesting) example of this is how all those "Mars attacks" / alien invasion / body snatcher stories really were about the Red Scare, basically "what if Communism was infiltrating our society!"