It was executed - you know this because your Home Directory was removed.
It may be that the rm -rf command was executed, then the system put up a warning in regards to the tail: ".cache/opera"
As that message is unknown, I cannot verify it.
But auto remove should not remove the Home Directory. "rm-rf 'Home Directory'" WILL remove it - and you input that command - and it was removed. It's an open and shut case.
That being said... there is a TYPO in your command. You have a space that should not be there.
The instructions wanted you to run:
rm -rf /home/$USER/.cache/opera
But you ran:
rm -rf /home/$USER/ .cache/opera
Please see This Thread:
I wish tutorials did not blithely throw the rm -rf command around without giving a crash course on how to use it and how to avoid problems with it.
That YouTube guide belongs in the Wall of Shame.