I find that these terms mean different things to different people. Agile in particular can be so many things. Some of the great agile teams I know of have chosen to take the goal of what good development would look like from DevOps, saying that they’re living a post-agile era of agile.
The question I find interesting is if it matters that people use the terms interchangeably or as if they are related. I’ve had some amazing conversations where I learn a lot, starting from trying to figure out what Agile or DevOps means to the person.