While I agree with everything you've said, I had heard the game (the clone) was going to be free
Which just begs the question of "Why do this in the first place if it isn't for monetary gain?"
Though I could be wrong
General Steam exposure, legitimization as a dev/pub by padding release list, monetization via item drops, monetization via telemetry (if injected), monetization via cryptominer (if injected). There are many ways to gain from Steam by publishing a free game.
Please, get an attorney and have them file a DMCA (which proxies out your personal information from being communicated to the thief). People like this don't deserve to get away with their crimes.