To be honest, I don't think most people's first interpretation of someone's claim to a "Discord-esque feel" when describing the UX of their open-source IRC client is that it's therefore riddled with dark patterns to sell an upgraded version of the service. I think it's probably more likely that they were referring to the general layout (eg: having circular server icons as a vertical list on the left hand side). I'm guessing that that's also why they mentioned Slack, since that has the same layout too.