Kanel is an en word. If you were to speak about some specific cinnamon, like, say, the cinnamon you bought in a specific store, you would say (den här) kanelen är god. But when you speak about the taste of cinnamon in general, you use the neuter form.
So when you say kanel är gott you are talking about cinnamon in general.
Blehg gave some more examples of this here: https://www.duolingo.com/comment/5948879