The problem of this whole discussion is that they try to confuse as much as they can by using terminology that surely sounds like they're doing "Open Source".
Read this: https://www.confluent.io/blog/license-changes-confluent-plat... Yeah, they don't write "The Confluent Community License is an Open Source License", but they use the term a whole lot and they also don't clearly write the accurate thing: "We're no longer using an Open Source license."
I think this whole thing would be much less of a controversy if some companies just said clearly: "We tried the Open Source way, it didn't work for us, now we do something different." But they don't want to be that company, instead they use all kinds of confusing terminology to obscure that fact and try to be the "We no longer use open source, but we surely want you to believe that we still do"-company.