As an InspIRCd developer you must also be aware that it only takes minutes for anyone to patch an IRC daemon to log chats. I don't think the lack of such a feature in core inspircd indicates anything.
You can use OTR for private IRC chats and an IRCv3 contributor is currently working on an end-to-end encryption system suitable for use in IRC channels so if you're concerned about your privacy you are welcome to use those.