I don't see the justification for speaking poorly of their users. Is convenience a bad thing now? Why do I want other image hosts hosting my images instead? What's the difference between putting them there and a chat platform from a privacy or centralization standpoint? I know for a fact many people use slack to trade images they don't want on the public net. So then I need to host a private image host too? That's a bit silly.

IRC is a fine platform. That doesn't mean it's what everybody needs/wants.