It could be that the first story caught his attention more than the others. Maybe it had a unique element or topic that appealed to him specifically. Another possibility is that he simply hasn't gotten around to the rest yet.
There could be various reasons. Perhaps the first story had a theme or style that resonated with him. Or, it might have been recommended to him and he focused only on that one. It's also possible that he's waiting for the right moment to check out the others.
Maybe he didn't have enough time to see the others. Or he might have found the first one particularly interesting.