This is an ongoing debate in the medium and I certainly do not have a solid opinion yet. This is just an attempt to jot some thoughts down and maybe I'll change my idea on some of them later.
On one side, you have what I call "purists" who believe that good sci-fi must always be introspective, thought-provoking, speculative. They believe that if the story does anything other than make you think about what the future holds for humanity and how we might choose the most positive solutions to our problems, then that story is trash. The pure sci-fi story wins the awards.
On another side, you have writers who just want to have a good time telling a fun story. They place their heroes into a time or environment that we currently can not reach (or might soon) then they kind of roll some dice to see what befalls the characters until the end of the story is reached. This story could be an action adventure, an epic tale of cosmic empires clashing, a time travel or alternate dimension tale of hi-jinx and swashbuckling. These stories do not win many awards, unless the story is a blend of purist speculation and fun.
I understand some of the origins of the debate. In the past, sci-fi was so broad and undisciplined that is was often confused with tales of medieval fantasy and magical tales. When the speculative authors emerged, the brought with them some direction for the genre. The stories that they wrote, the ones that made the reader stop mid-sentence and think for while, were a fresh experience. The science in the speculative stories was based on real, actual science and some of it was very cutting edge.
Some of that cutting edge science has not aged well. Since some of the thought provoking speculation was based on that science, some of the stories themselves have unraveled. That does not mean the "other" old science fiction has fared any better. As modern tastes and intelligence has changed, many of those stories have proven to be nothing more than silly tales of fanciful ideas that no longer have a place in modern society.
A purist will tell you that just because the story has a space ship or time travel does not mean it is a sci-fi story.
I understand the idea. A part of me wants to agree with it. At this time, however, I can't. A space ship suggests future technology, time travel suggests future science. A weapon that does not currently exist in the modern era, but has a place in your story suggests future warfare. These are the components, or tools, used to tell a sci-fi story. It may be a story that makes you feel dumber after having read it, but it is a sci-fi story none the less.
Those are my thoughts on the topic so far.