It is enough to search for a pornstar's name to find porn in the Reddit app. This works even if you don't have an account and NSFW content is disabled. While it's not as "simple" as a porn keyword, it is almost certain people do this. Reddit relies on people tagging their content as NSFW, but of course this is not something they can enforce 100%. And once you find an account posting NSFW, you can access all their NSFW posts even if they were made on subreddits that are hidden to you if you search for them explicitly in the search bar.
By the way, when I typed the actress' first name, I was already being suggested a subreddit dedicated to sharing nude pictures of another woman with the same name. Again, I used the app as it comes straight out of the App Store without logging in or changing anything.
Anyone that has ever set foot on Reddit or 4chan knows that Wickr is heavily used to share child pornography, and revenge pornography. Entire subreddits have disappeared for this reason [1]. I wonder how AWS is going to deal with this. Unfortunately due to the nature of the app, they can probably safely say that they were "no aware of it"...
By the way, when I typed the actress' first name, I was already being suggested a subreddit dedicated to sharing nude pictures of another woman with the same name. Again, I used the app as it comes straight out of the App Store without logging in or changing anything.