I mean, every user of that channel can do that as well. It's just that there shouldn't be expectation of privacy on a Discord channel unless you know and trust every participant.
Message reading bots are very useful for many things. Limiting them because of privacy concerns sounds like a loss for no gain to me. There isn't any privacy on Discord to begin with.
+ AFAIK Discord said they aren't going to completely remove message access, just lock it behind a privilileged intent. What's stopping malicious developers from adding features such as bad link detection, chat activity leveling system, thus giving them a reason to say to Discord, hey, we need message access, and then using the message access for these malicious reasons.
Message reading bots are very useful for many things. Limiting them because of privacy concerns sounds like a loss for no gain to me. There isn't any privacy on Discord to begin with.