I am pretty sure that's the standard legalese for most platforms. Reddit and YouTube also effectively have the same wording.

I would struggle to find a major platform without it.

Reddit [0]

> When Your Content is created with or submitted to the Services, you grant us a worldwide, royalty-free, perpetual, irrevocable, non-exclusive, transferable, and sublicensable license to use, copy, modify, adapt, prepare derivative works from, distribute, perform, and display Your Content and any name, username, voice, or likeness provided in connection with Your Content in all media formats and channels now known or later developed.

YouTube [1]

> By providing Content to the Service, you grant to YouTube a worldwide, non-exclusive, royalty-free, sublicensable and transferable license to use that Content (including to reproduce, distribute, prepare derivative works, display and perform it) in connection with the Service and YouTube’s (and its successors’ and Affiliates’) business, including for the purpose of promoting and redistributing part or all of the Service.

0: https://www.redditinc.com/policies/user-agreement#text-conte...

1: https://www.youtube.com/static?template=terms#a294b3b51f

Just because it is widely used doesn't mean that from user PoV it is very overreaching.

They don't claim copyright, they ask (since this is a EULA and they don't tend to stand up very well in court) for a license to do the things you expect of a chat client with the stuff you post on the chat client (the big distinction being this doesn't restrict what you can do with it at all). It's a symptom of how broken copyright is that it's necessary. A really important part of that clause is "in connection with operating and providing the Service". While there's possibly a wide range of interpretations of exactly what that would mean (for example, could they incorporate any code you post on the platform into the code used for the server or client?), it means they can't do whatever they want with the content.