Stealing the project name was a mistake. The authors are right to be upset by the fact that people used to get their project when they did "yum install dstat" but now are getting a completely different (and not completely compatible) project. I think a lot of the friction could have gone away if they had just named it "pcp-dstat" or something similar, but instead they essentially took this person's namespace without discussion, and really for no good reason that I can tell.
The other issue is that forking a project without even talking with the people running it is a very touchy subject. Ultimately it does look like the project was dead- even to the point where people were asking to contribute but not getting responded to, and the fact that python2 is EOL and python3 support wasn't added until after this drama started shows that the project wasn't really "active". So while I do think they should have reached out, I totally understand why that slipped their mind.
So at this point I think RedHat should apologize and fix the package name.