The people doing the discrimination are the groups that choose Discord as their communications tool.
They are excluding all users who can’t get Discord accounts, such as those who can’t agree to the Discord TOS, for example. Free software projects and other public benefit groups should not be discriminatory.
They’re also banning political cartoons within their group’s
communications, by implicit inclusion of the Discord TOS which bans several common, normal, reasonable types of communication.
I’m a paying member of a local nonprofit organization; they use Discord exclusively to communicate. I am excluded from all of the discussions as a result of my not being able to safely get a Discord account. That’s discrimination whether you like to acknowledge it or not.