Your Listeners = Their Listeners
People who are interested in a topic don’t just stop with a single source of information. There’s no such thing as “your listeners,” because the people who listen to your podcast are also listening to other podcasts on related (or even the same) topics.
On the flip side of this, “their listeners” are also listening to you.
Someone else’s success isn’t your failure. And in podcasting, their success is often your success as well.