There is a difference, if they renamed "kind" to "type" their stuff would not work anywhere else, and no one wants that so they don't do it. But if I said "Nostr is just text" but someone added a picture URL as text and someone else rendered that automatically that wouldn't prevent their text URLs from being shown in other clients. I'm sure you get the difference. In this case what would happen (if I'm right in my assumptions, and unfortunately) is that most users would migrate to the client that displayed the images and not just the URL text. Maybe you wanted me to write in the protocol that URLs are forbidden entirely and content with URLs must be treated as invalid. That could have worked for a while, but relaxing assumptions is a developer's primary ability (Postel's law, that's how protocol bloat happens always -- just take a look at any JavaScript codebase and see how they check if a thing is not null, then if it has some property, then some sub-property, then if it's a function, then call it while catching exceptions, then check if the returned value is of the expected type and so on). Also someone would end up introducing some weird roundabout way of sharing images without encoding them as URLs. If you look at twtxt (which is closest to your dream of pure text) even with the very few users they have they have already developed twtxt "extensions" (not hosted in the original twtxt protocol description page) that support mentions, threading, reposts, probably images and, who knows, maybe they even have livestreams there already.