Honestly a diet of just those foods sounds miserable - I'm also allergic to nuts so that's not an option either. Kudos to the people that decide to limit their diet so much to go vegan, but no one is obligated to do so. People are allowed to be excited that there is going to be a more ethical version of food they enjoy
Discord has been making a lot of bad decisions lately but imo this isn't one of them. It's not like they're forcing every server to setup paid channels.
Currently, many creators have Patreons setup and allow varying levels of access to their Discord servers based on Patreon tiers. Literally all this change does is give creators the option to do this entirely through Discord rather than using Patreon.
This is nothing new. Just a slightly different way to handle monetization.