One hackneyed reason that some folks give for not wanting to expose their RSS is wanting some level of legibility into their subscribers. I recently learned that many large RSS readers actually expose high-level analytics numbers [^1] so you can get an estimate of RSS readership that way, too. Would love for more readers to support this functionality: as far as I can tell across all of the RSS feeds my product exposes, the only supporting clients of this faux protocol are NewsBlur, Feedly, Feedbin, and inoreader.
[^1]: ht to Darek Kay's blog post, https://darekkay.com/blog/rss-subscriber-count/, for alerting me to this fact!