Very dramatic presentation for something very mundane. Every computer has "remote control" of some sort - if anything, to install security updates. Without security updates, there is a good chance your devices will turn into huge botnet at some point. I believe that EU CRA even requires such backchannel.
I can agree, however, that refusing to work without internet is be too much for the device which can support offline operation.
Remotely triggered security updates are very common. But my experience in seeing remote command execution to disable a device is bit concerning. Having rtty software installed is another nightmare. Not sure if you call all these mentioned in the article mundane
You are letting it connect to manufacturer's servers, and allow it to execute unknown commands. You know that one command, "501", disables vacuum. There is a very good chance that there is some other remote command with "remote exec random command" functionality, you just didn't see it. There is also a good chance that there are already commands for any creepy things you might want to be worried about (like send camera video).
So, given that, why are you worried about rtty specifically? It's likely a redundant debugging channel in case the main app crashes. It does not add any special functionality that main app does not have.
Now re "disabling the device" - I wonder what command means? Could it be something like "local logs buffer full, pausing operation until upload is done"? Thinking about this more, your blog basically says:
1. vacuum works fine
2. you disable half of the ports on the firewall
3. vacuum stops working
4. you send it for warranty repair
I was very surprised to see that 4 was "send it to warranty repair", instead of "re-open ports on firewall and see if it starts to work now". Did you try this? If not, then it's pretty likely the vacuum was not "bricked" in any sense, but rather was waiting forever for its logs to get uploaded.
Allegedly. The article while extremely heavy on the drama provides no real details at all apart from one log message. And they're totally extrapolating out what the start of the log message might mean.
I can agree, however, that refusing to work without internet is be too much for the device which can support offline operation.